This work was supported by the New College of Interdisciplinary Arts and Sciences at Arizona State University, Applied Maths NV, and by the National Science Foundation (ROA Supplement to Award No. MCB0604300). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

주의 : 모든 환경에서 미확인 된 박테리아는 병원성 할 수 있으며, 적절한 바이오 안전성 프로토콜을 사용하여주의하여 취급해야합니다. 라이브 문화에 대한 작업은 생물 안전 레벨 2 (BSL-2) 절차를 사용하여 클래스 II 생물 안전 캐비닛에서 수행해야합니다. BSL-2 절차에 대한 자세한 내용은 페이지 33-38 &quot;미생물 및 생물 의학 연구소에서 바이오 안전성&quot;CDC / NIH의 제목 설명서,에서 사용할 수 있습니다. 문서에서 온라인으로 볼 수 있습니다 <a href="http://www.cdc.gov/biosafety/publications/bmbl5/BMBL.pdf">http://www.cdc.gov/biosafety/publications/bmbl5/BMBL.pdf</a> . 실험복 / 가운, 보호 안경, 니트릴 또는 라텍스 장갑을 포함 적절한 개인 보호 장비 (PPE)를 착용해야합니다. 표준 미생물 학적 방법과주의 사항을 준수해야하며, 생물학적 폐기물은 적절히 폐기해야합니다. 이 데모에 사용 된 박테리아는 Kartchner 동굴에서 분리되었다,AZ, USA, 건조 스펠 레오 뎀, 흐름 돌, 촉촉한 스펠 레오 뎀과 종유석 드립 (표 1) 등 4 개 환경에서. 모든 균주의 16S rDNA 염기 서열 분석에 의해 확인 된 25 % 글리세롤 2 B-R 매체에서 -80 ° C에 보관 하였다. 모든 실험은 실온에서 완료 하였다. 참고 : 우리는 데이터베이스 구축 및 미지의 질량 스펙트럼에 대한 질량 스펙트럼을 획득하기 위해 같은 샘플 준비 방법을 사용하는 것이 좋습니다. 시료 제조 방법은 스펙트럼의 품질 및 재현성에 영향을 미치는 세 이전에 도시되었다. 다른 샘플 준비 방법을 사용하는 것은 바람직하다 (변형 수준에서 예) 미지의 잘못된 식별, 특히 높은 분류 학적 해상도의 원인이 될 수 있습니다. MALDI 대상 1. 증착 주의 : 여러 프로토콜 단백질 추출물 GUID에 따라 이용해야 산 및 유기 용매의 사용을 필요로 수득각각의 재료 안전 데이터 시트 (MSDS)에 포함 elines 및 정보. 적절한 보호구 착용해야하며, 사용되는 화학 물질의 종류와 양에 따라 달라집니다 (예를 들어, 아세토 니트릴 등의 독성, 가연성 솔벤트의 상당 수, 작업 할 때 / 가운, 장갑, 보호 안경, 그리고 호흡 보호 장치를 사용해야합니다 실험실 코트, 포름산과 트리 플루오로 산과 같은 부식성 산). <ol><li> 스테인레스 스틸 MALDI 표적 판에하고 건조 할 수 있도록 (해당 앞에서 설명한 프로토콜 11-13을 사용하여 얻은)에는 가능한 세포를 포함하지 않는 단백질 추출물 μL 보증금 1. 1 ㎕의 매트릭스 용액 (α 아노 -4- 하이드 록시 - 신 남산 용액)와 단백질 건조 추출물을 오버레이하고 건조시켜야. </li><li> 각 생물 복제의 경우, 기술 복제합니다 (5-20 기술 회 반복) 적절한 수의 자리. 여기서, 각 생물 복제에 대 한 (10) 기술 복제하고 3 생물 복제합니다 w를 발견오히려 준비했다. 참고 : 우리는 단백질 추출 시료 전처리 법을 이용하는 경우 연마 MALDI 스틸 타겟 판을 사용하는 것을 권장. 스틸 그라운드 대상 플레​​이트를 사용하여 확산 및 개별 샘플 우물 외부의 다른 샘플의 의도하지 않은 혼합의 원인이 될 수 있습니다. </li><li> 보증금 1 μL의 calibrant의 대상 판에 표준이 건조 할 수 있습니다. 1 μL 매트릭스 솔루션을 오버레이하고 건조 할 수 있습니다. </li><li> 음성 대조군으로 대상 접시에 보증금 2 μL 매트릭스 솔루션입니다. </li></ol> 2. 질량 스펙트럼 취득 <ol><li> 질소 레이저 (λ = 337 ㎚)를 구비 한 MALDI-TOF 질량 분석기를 사용하여 브루 커 FlexControl 소프트웨어를 이용하여 동작. </li><li> 100 샷 단위로 500 레이저 샷의 축적에 의해 긍정적 인 선형 모드에서 각 질량 스펙트럼을 수집합니다. 20kV의에 이온 원 (1) 전압을 설정; 이온 소스 (2) 18.15 kV의 전압을; 및 9.05 kV의에 렌즈 전압. 이러한 매개 변수는 악기 정시 참고및 FIC는 최적의 결과를 얻기 위해 다른 악기에 대한 조정이 필요할 수 있습니다. </li><li> 충전 당 2 ~ 20 kDa의 자동화 된 스펙트럼 평가를위한 대량으로 충전 범위를 설정합니다. 중심 피크 검출 알고리즘을 사용합니다. (100) 다에서 최소 해상도 임계 값을 설정합니다. 100에서의 최소 세기 임계 값을 설정 2.에서 역치 잡음비 (S N)에 신호를 설정한다. </li></ol> 3. 데이터베이스 건설 <ol><li> 데이터베이스 설계 <ol><li> &quot;새 데이터베이스 마법사&quot;를 사용하여 BioNumerics 7.1에서 새 데이터베이스를 만듭니다. </li><li> &quot;실험 유형&quot;패널에서 명령을 사용하여 스펙트럼 실험 유형, 예를 들어,을 Maldi를 만듭니다. </li><li> &quot;데이터베이스 디자인 패널&quot;을 이용하여 레벨을 작성합니다. 사용하여 새로운 수준의 추가 &quot;데이터베이스&quot;메뉴의 명령 &quot;레벨&gt; 새로운 차원의 ... 추가&quot;. 여기에, &quot;종&quot;수준 &quot;생물 복제&quot;수준 &quot;과&quot;기술 복제 &quot;수준 respectiv를 만들엘리. </li></ol></li><li> 가져 오기 및 원시 질량 스펙트럼을 전처리 <ol><li> &quot;파일&quot;메뉴에서 &quot;내보내기&gt; 질량 스펙트럼&quot;명령을 클릭하여 FlexAnalysis를 사용하여 .txt 파일로 원시 질량 스펙트럼을 보냅니다. </li><li> 복제물 기술적 수준에서 데이터베이스로 원료 질량 스펙트럼 (.txt 파일)를 가져. </li><li> 원시 질량 스펙트럼을 미리 처리. <ol><li> 가져 오기 및 재 샘플 (차 피팅 알고리즘을 사용하여). </li><li> (50 점의 크기와 회전 디스크 포함) 기준 빼기를 수행합니다. </li><li> (창 20 점의 크기와 10 점의 베타 카이저 창) 소음 [연속 웨이블릿 변환 (CWT)], 부드러운을 계산하고, 두 번째 기본 공제 (200 점의 크기와 디스크를 압연)을 수행합니다. </li><li> [: 10 (N S) 잡음 비율 최소한의 신호와 CWT] 피크를 감지합니다. </li></ol></li><li> 전처리 한 후, 같은 피크를 포함하는 피크 목록과 같은 각각의 질량 스펙트럼의 특성 패턴을 저장크기, 피크 강도, S : 데이터베이스 N 등. </li></ol></li><li> 복합 질량 스펙트럼을 만들기 <ol><li> &quot;분석&quot;메뉴의 &quot;... 요약&quot;명령을 사용하여 사전 처리 된 스펙트럼에서 복합 스펙트럼을 만듭니다. 목표 수준으로 &quot;생물 복제&quot;를 선택합니다. </li><li> 여기에서, &quot;생물 복제&quot;수준에서 그 분리에 대 한 세 가지 복합 질량 스펙트럼의 결과로, 그 식민지의 복합 질량 스펙트럼을 산출하기 위해 같은 식민지의 10 기술 복제물의 질량 스펙트럼을 결합한다. </li><li> 여기, 즉 &quot;종&quot;레벨에서 분리하기위한 하나의 복합 스펙트럼을 생성하기 위해 세 가지 복합 스펙트럼을 요약한다. 참고 : 복합 스펙트럼은 기술 복제물의 포인트 별 평균입니다. 95 % 이상 (기본 설정)의 평균 유사도 (피어슨 상관 관계)를 복제 복합에서 제외됩니다. 그들은 (75 %에있는 경우 복합 스펙트럼의 봉우리 만이라고합니다포함 된 복제물의 기본 설정). 생물학적 복제판 들어, 이러한 설정은 각각 90 및 60 %였다. </li></ol></li></ol> 4. 질량 스펙트럼 데이터 분석 <ol><li> 데이터베이스의 항목을 선택하고 &quot;비교&quot;패널에서 &quot;새로운 비교 만들기&quot;명령을 클릭하여 비교를 만들 수 있습니다. </li><li> 여기에, 비교 및​​ 분석을 보여주기 위해 &quot;기술 복제&quot;및 / 또는 &quot;생명 복제&quot;수준에서 질량 스펙트럼을 사용합니다. </li><li> 비슷한 기반 클러스터 분석과 다차원 스케일링 (MDS) <ol><li> 색상 그룹을 만듭니다. 세 가지 생물학적 복합 질량 스펙트럼을 선택하고 해당 분리에 대 한 그룹을 만듭니다 &quot;그룹&quot;메뉴의 명령 &quot;선택에서 만들기 새 그룹&quot;을 클릭합니다. 자동 이러한 세 질량 스펙트럼에 사용 색을 지정한다. </li><li> 또한,의 명령을 사용하여 해당 색상으로 필드 상태를 정의하는 &quot;이 정의 필드를 기준으로 모든 그룹이 그룹에 대해 정의 된 같은 색을 사용하도록 데이터베이스 항목 &quot;패널. </li><li> 클러스터 분석을 수행합니다. &quot;클러스터링&quot;메뉴의 &quot;클러스터 분석을 계산&quot;명령을 클릭합니다. 비교 설정 1 페이지, &quot;피어슨 상관 관계&quot;를 선택하고 기본값으로 다른 매개 변수를 둡니다. 2 페이지에서 &quot;UPGMA&quot;를 선택합니다. 그런 다음 &quot;마침&quot;을 클릭합니다. </li><li> &quot;통계&quot;메뉴의 MDS를 사용하여 플롯 &quot;다차원 스케일링을 ...&quot;명령을 얻습니다. </li></ol></li><li> 피크 일치 <ol><li> &quot;실험&quot;패널의 스펙트럼 유형 &quot;을 Maldi&quot;을 클릭합니다. 그런 다음 &quot;레이아웃&gt; 이미지보기&quot;를 선택합니다. 스펙트럼 겔 밴드로 표시됩니다. </li><li> &quot;스펙트럼&quot;메뉴에서 &quot;피크 일치를 수행&quot;명령을 사용하여 피크 매칭을 수행합니다. </li></ol></li><li> 피크 클래스 식별 <ol><li> 주성분 분석 (PCA)을 수행. 강조 &quot;MALDI 실험 &quot;실험의 유형&quot; &quot;패널과 사용&quot;PCA를 수행하는 통계 &quot;메뉴&quot;에서 명령 &quot;주 구성 요소 분석을 .... </li><li> 양방향 클러스터링을 수행합니다. &quot;비교&quot;창에서 &quot;통계&gt; 매트릭스 마이닝을 ...&quot;을 클릭합니다. 피크 클래스에 정합 피크의 세기는 서로 다른 색상 (열 맵)를 이용하여 표현된다. </li></ol></li></ol> 사용자 지정 데이터베이스 5. 박테리아 식별 <ol><li> 비슷한 계수 기반 방법 <ol><li> 비교를 만들고 단계 4.3.3에 설명 된대로 &quot;기술 복제&quot;수준의 질량 스펙트럼을 기반으로 Dendrogram이를 생성합니다. 유사성의 비교를 위해 Dendrogram이를 저장합니다. </li><li> &quot;선택 항목을 확인&gt; 분석&quot;알 수없는 질량 스펙트럼을 선택하고을 클릭합니다. 확인 대화 상자가 나타납니다. </li><li> &quot;비교를 기반으로&quot;분류 유형 (또는 저장 classif를 선택IER) 및 &quot;다음&quot;을 클릭합니다. 다음 페이지에서 참조 비교로 저장 Dendrogram이를 선택하고 &quot;다음&quot;을 클릭합니다. </li><li> 식별 방법으로 &quot;기본 유사성&quot;을 선택하고 &quot;다음&quot;을 클릭합니다. </li><li> 채점 방법으로 &quot;최대 유사성&quot;을 선택합니다. 각 매개 변수에 대한 적절한 임계 값과 최소값의 차이 값을 입력하고 &quot;다음&quot;을 클릭합니다. </li><li> 계산이 완료되면, 확인 창이 나타납니다. &quot;결과&quot;패널에서 가장 잘 알 수없는 일치하는 데이터베이스의 구성원이 나열됩니다. </li><li> 식별 프로젝트를 저장하고 &quot;확인 프로젝트&quot;패널에서 &quot;교차 유효성 검사 분석&quot;명령을 사용하여 ID를 확인합니다. </li></ol></li><li> 잠재적 바이오 마커 기반 방법 <ol><li> 피크 클래스를 정의합니다. &quot;매트릭스 광업&quot;창에서 공통적 인 특징을 공유하는 피크 세트를 선택하고 정시 이러한 피크를 정의FIC 피크 클래스 (잠재적 인 바이오 마커)를 사용하여 &quot;스펙트럼&gt; 피크 클래스 유형을 ... 관리&quot; &quot;비교 창&quot;에서. </li><li> 여기에, 모든 15 균주에 대한 격리 각 특정 피크 클래스를 정의합니다. </li><li> 미지의 질량 스펙트럼을 선택하고, 전술 한 바와 같이 정의 피크 클래스 이러한 스펙트럼의 피크와 일치. </li></ol></li></ol>

<ol>
	<li>Sandrin, T. R., Goldstein, J. E., Schumaker, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MALDI+TOF+MS+profiling+of+bacteria+at+the+strain+level:+A+review.">MALDI TOF MS profiling of bacteria at the strain level: A review.</a> Mass Spectrom Rev. 32 (3), 188-217 (2013).</li><li>Siegrist, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discrimination+and+characterization+of+environmental+strains+of+Escherichia+coli+by+matrix-assisted+laser+desorption/ionization+time-of-flight+mass+spectrometry+(MALDI-TOF-MS).">Discrimination and characterization of environmental strains of Escherichia coli by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).</a> J Microbiol Meth. 68 (3), 554-562 (2007).</li><li>Goldstein, J. E., Zhang, L., Borror, C. M., Rago, J. V., Sandrin, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Culture+conditions+and+sample+preparation+methods+affect+spectrum+quality+and+reproducibility+during+profiling+of+Staphylococcus+aureus+with+matrix-assisted+laser+desorption/ionization+time-of-flight+mass+spectrometry.">Culture conditions and sample preparation methods affect spectrum quality and reproducibility during profiling of Staphylococcus aureus with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.</a> Lett Appl Microbiol. 57 (2), 144-150 (2013).</li><li>Benagli, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+MALDI-TOF+MS+identification+database+at+genospecies+level+for+clinical+and+environmental+Aeromonas+strains.">A rapid MALDI-TOF MS identification database at genospecies level for clinical and environmental Aeromonas strains.</a> Plos One. 7 (10), (2012).</li><li>Sauer, S., Kliem, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+spectrometry+tools+for+the+classification+and+identification+of+bacteria.">Mass spectrometry tools for the classification and identification of bacteria.</a> Nat Rev Microbiol. 8 (1), 74-82 (2010).</li><li>Bohme, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SpectraBank:+An+open+access+tool+for+rapid+microbial+identification+by+MALDI-TOF+MS+fingerprinting.">SpectraBank: An open access tool for rapid microbial identification by MALDI-TOF MS fingerprinting.</a> Electrophoresis. 33 (14), 2138-2142 (2012).</li><li>Walker, J., Fox, A. J., Edwards-Jones, V., Gordon, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intact+cell+mass+spectrometry+(ICMS)+used+to+type+methicillin-resistant+Staphylococcus+aureus:+media+effects+and+inter-laboratory+reproducibility.">Intact cell mass spectrometry (ICMS) used to type methicillin-resistant Staphylococcus aureus: media effects and inter-laboratory reproducibility.</a> J Microbiol Meth. 48 (2-3), 117-126 (2002).</li><li>Ruelle, V., El Moualij, B., Zorzi, W., Ledent, P., De Pauw, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+identification+of+environmental+bacterial+strains+by+matrix-assisted+laser+desorption/ionization+time-of-flight+mass+spectrometry.">Rapid identification of environmental bacterial strains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.</a> Rapid Commun Mass Sp. 18 (18), 2013-2019 (2004).</li><li>Sedo, O., Sedlacek, I., Zdrahal, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sample+Preparation+Methods+for+Maldi-MS+Profiling+of+Bacteria.">Sample Preparation Methods for Maldi-MS Profiling of Bacteria.</a> Mass Spectrom Rev. 30 (3), 417-434 (2011).</li><li>Swatkoski, S., Russell, S., Edwards, N., Fenselau, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+a+model+virus+using+residue-specific+chemical+cleavage+and+MALDI-TOF+mass+spectrometry.">Analysis of a model virus using residue-specific chemical cleavage and MALDI-TOF mass spectrometry.</a> Anal Chem. 79 (2), 654-658 (2007).</li><li>Freiwald, A., Sauer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phylogenetic+classification+and+identification+of+bacteria+by+mass+spectrometry.">Phylogenetic classification and identification of bacteria by mass spectrometry.</a> Nat Protoc. 4 (5), 732-742 (2009).</li><li>Drevinek, M., Dresler, J., Klimentova, J., Pisa, L., Hubalek, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+sample+preparation+methods+for+MALDI-TOF+MS+identification+of+highly+dangerous+bacteria.">Evaluation of sample preparation methods for MALDI-TOF MS identification of highly dangerous bacteria.</a> Lett Appl Microbiol. 55 (1), 40-46 (2012).</li><li>Lasch, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MALDI-TOF+mass+spectrometry+compatible+inactivation+method+for+highly+pathogenic+microbial+cells+and+spores.">MALDI-TOF mass spectrometry compatible inactivation method for highly pathogenic microbial cells and spores.</a> Anal Chem. 80 (6), 2026-2034 (2008).</li><li>Usbeck, J. C., Kern, C. C., Vogel, R. F., Behr, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+experimental+and+modelling+parameters+for+the+differentiation+of+beverage+spoiling+yeasts+by+Matrix-Assisted-Laser-Desorption/Ionization+Time-of-Flight+Mass+Spectrometry+(MALDI-TOF+MS)+in+response+to+varying+growth+conditions.">Optimization of experimental and modelling parameters for the differentiation of beverage spoiling yeasts by Matrix-Assisted-Laser-Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in response to varying growth conditions.</a> Food Microbiol. 36 (2), 379-387 (2013).</li><li>Del Chierico, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MALDI-TOF+MS+proteomic+phenotyping+of+filamentous+and+other+fungi+from+clinical+origin.">MALDI-TOF MS proteomic phenotyping of filamentous and other fungi from clinical origin.</a> J Proteomics. 75 (11), 3314-3330 (2012).</li><li>Vitale, R., Roine, E., Bamford, D. H., Corcelli, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+fingerprints+of+intact+viruses+by+MALDI-TOF/mass+spectrometry.">Lipid fingerprints of intact viruses by MALDI-TOF/mass spectrometry.</a> Bba-Mol Cell Biol L. 1831 (4), 872-879 (2013).</li><li>Zhang, L., Borror, C. M., Sandrin, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+designed+experiments+approach+to+optimization+of+automated+data+acquisition+during+characterization+of+bacteria+with+MALDI-TOF+mass+spectrometry.">A designed experiments approach to optimization of automated data acquisition during characterization of bacteria with MALDI-TOF mass spectrometry.</a> Plos One. 9 (3), (2014).</li><li>Christner, M., Rohde, H., Wolters, M., Sobottka, I., Wegscheider, K., Aepfelbacher, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+identification+of+bacteria+from+positive+blood+culture+bottles+by+use+of+matrix-assisted+laser+desorption-ionization+time+of+flight+mass+spectrometry+fingerprinting.">Rapid identification of bacteria from positive blood culture bottles by use of matrix-assisted laser desorption-ionization time of flight mass spectrometry fingerprinting.</a> J ClinMicrobiol. 48 (5), 1584-1591 (2010).</li></ol>

Authors Vranckx and Janssens are employees of Applied Maths NV, the manufacturer of data analysis software used in this video. Applied Maths NV provided select software modules highlighted in this video as well as a portion of the publication costs associated with this video.

이 데모는 특성화 및 MALDI-TOF MS와 사용자 지정 데이터베이스를 사용하여 세균의 식별의 세부 절차를 보여 주었다. 예를 들어 전통적인 분자 방법과 비교하여, 16S rDNA의 염기 서열, MALDI-TOF MS 기반 지문 방법은 다양한 박테리아의보다 신속한 식별을 용이하게한다. 견고성으로 인해,이 기술은 널리 임상 환경에서 설정 1,14-16에서 박테리아, 바이러스, 곰팡이 및 효모를 특성화하기 위해 사용된...

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has been shown to be a rapid and reliable tool for identification of bacteria at the genus, species, and in some cases, strain levels1-4. MALDI-TOF MS ionizes biological molecules (typically proteins) that originate from cell surfaces, intracellular membranes, and ribosomes from bacterial whole cells or protein extracts1,5. The resulting peaks form characteristic patterns or &#8220;fingerprints&#8221; of the bacteria analyzed1. Identification of bacteria is based on these mass-to-charge &#8220;fingerprints&#8221;. 
Two of the most commonly used identification strategies are library-based and bioinformatics-based strategies1. Library-based approaches involve comparing the mass spectra of unknowns to previously collected mass spectra of known bacteria in databases/libraries for identification. Commercially available software, such as BioNumerics, Biotyper, and SARAMIS software packages, as well as open source software tools, such as SpectraBank6, are available to facilitate the comparison and quantification of similarity between mass spectra of unknowns and reference bacteria. Bioinformatics-based approaches usually rely on fully sequenced genomes of bacteria for identification. In contrast to library-based approaches which do not involve identification of the biological nature of particular peaks, bioinformatics-based approaches involve protein identification1. 
The majority of recent MALDI fingerprint-based studies have used library-based approaches to identify bacteria1. Library-based approaches require construction of databases and comparison of the similarity between mass spectra. Studies show that many experimental procedures, such as medium3,7, cultivation time8, sample preparation method3, and matrix used9, affect the mass spectra obtained. Furthermore, some closely-related species and strains generate spectra with only subtle differences. Thus, library-based approaches require rigorously standardized procedures to generate highly reproducible mass spectra between replicates. Minor variations in protocols may compromise the efficacy of identification, especially at the subspecies and strain levels1,3,10. However, neither manufacturer-provided reference databases nor reported custom databases include visually documented procedures for database construction and/or application of a data analysis pipeline. For this reason, the objective of this work was to develop, apply, and demonstrate a comprehensive and detailed procedure for library-based bacterial identification using MALDI-TOF MS. 
In this demonstration, mass spectra of 15 bacteria isolated from a karstic environment (Kartchner Cavern, AZ, USA) were collected and imported into software to construct a model database. Data processing and the analysis pipeline were detailed using the model database. Finally, mass spectra of blind-coded bacteria which were randomly selected from these 15 bacteria were collected again and compared to the reference spectra in the model database for identification. Results show that bacteria can be correctly identified either based on similarity coefficients or potential biomarkers/peak classes.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>&#945;-cyano-4-hydroxy-cinnamic acid</td>
			<td>ACROS Organics</td>
			<td align="right">163440050</td>
			<td>&#8805; 97%, CAS 28168-41-8</td>
		</tr>
		<tr>
			<td>MALDI calibration kit</td>
			<td>Aigma-Aldrich</td>
			<td>MSCAL1-1KT</td>
			<td>This kit also contains acetonitrile, trifluoroacetic acid , sinapinic acid, etc.</td>
		</tr>
		<tr>
			<td>MALDI target plate</td>
			<td>Bruker Daltonics</td>
			<td align="right">280800</td>
			<td>Polished Steel</td>
		</tr>
		<tr>
			<td>Bruker Microflex LRF MALDI-TOF mass spectrometer</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bruker FlexControl software</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td>version 3.0</td>
		</tr>
		<tr>
			<td>Bruker FlexAnalysis software</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td>version 3.0</td>
		</tr>
		<tr>
			<td>Bionumerics software</td>
			<td>Applied Maths</td>
			<td></td>
			<td>version 7.1</td>
		</tr>
	</tbody>
</table>

use of maldi-tof mass spectrometry and a custom database to characterize bacteria indigenous to a unique cave environment (kartchner caverns, az, usa)

MALDI-TOF mass spectrometry has been shown to be a rapid and reliable tool for identification of bacteria at the genus and species, and in some cases, strain levels. Commercially available and open source software tools have been developed to facilitate identification; however, no universal/standardized data analysis pipeline has been described in the literature. Here, we provide a comprehensive and detailed demonstration of bacterial identification procedures using a MALDI-TOF mass spectrometer. Mass spectra were collected from 15 diverse bacteria isolated from Kartchner Caverns, AZ, USA, and identified by 16S rDNA sequencing. Databases were constructed in BioNumerics 7.1. Follow-up analyses of mass spectra were performed, including cluster analyses, peak matching, and statistical analyses. Identification was performed using blind-coded samples randomly selected from these 15 bacteria. Two identification methods are presented: similarity coefficient-based and biomarker-based methods. Results show that both identification methods can identify the bacteria to the species level.

이 데모에 건설 데이터베이스는 &quot;종&quot;, &quot;생물 복제&quot;와 &quot;기술 복제&quot;각각 (그림 1A)을 포함한 &quot;모든 레벨&quot;최고에서 최저 수준을 4 단계를했다. &quot;기술 복제&quot;수준의 기술 복제물의 모든 전처리 스펙트럼을 포함. &quot;생물 복제&quot;와 &quot;종&quot;레벨은 복합 (요약) 스펙트럼을 포함. &quot;모든 레벨&quot;모든 기술적 복제 스펙트럼뿐만 아니라 모든 복합 스펙...

Watch this Scientific Journal Video about Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment Kartchner Caverns, AZ, USA at JoVE.c

Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment Kartchner Caverns, AZ, USA

This work details procedures for rapid identification of bacteria using MALDI-TOF MS. The identification procedures include spectrum acquisition, database construction, and follow up analyses. Two identification methods, similarity coefficient-based and biomarker-based methods, are presented.

MALDI-TOF 질량 분석 및 사용자 지정 데이터베이스의 사용은 고유 동굴 환경 (Kartchner 동굴, AZ, USA)에 토착 박테리아의 특성을

MALDI-TOF mass spectrometry has been shown to be a rapid and reliable tool for identification of bacteria at the genus and species, and in some cases, ...

use-maldi-tof-mass-spectrometry-custom-database-to-characterize

Research

JoVE Journal

Biology

Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment (Kartchner Caverns, AZ, USA)

13.9K 조회수.  Arizona State University. This work details procedures for rapid identification of bacteria using MALDI-TOF MS. The identification procedures include spectrum acquisition, database construction, and follow up analyses. Two identification methods, similarity coefficient-based and biomarker-based methods, are presented. 

비디오: Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment Kartchner Caverns, AZ, USA

MALDI Sample Preparation: the Ultra Thin Layer Method

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) 1,2. The ultra-thin layer method involves the production of a substrate layer of matrix crystals (alpha-cyano-4-hydroxycinnamic acid) on the sample plate, which serves as a seeding ground for subsequent crystallization of a matrix/analyte mixture. Advantages of the ultra-thin layer method over other sample deposition approaches (e.g. dried droplet) are that it provides (i) greater tolerance to impurities such as salts and detergents, (ii) better resolution, and (iii) higher spatial uniformity. This method is especially useful for the accurate mass determination of proteins. The protocol was initially developed and optimized for the analysis of membrane proteins and used to successfully analyze ion channels, metabolite transporters, and receptors, containing between 2 and 12 transmembrane domains 2. Since the original publication, it has also shown to be equally useful for the analysis of soluble proteins. Indeed, we have used it for a large number of proteins having a wide range of properties, including those with molecular masses as high as 380 kDa 3. It is currently our method of choice for the molecular mass analysis of all proteins. The described procedure consistently produces high-quality spectra, and it is sensitive, robust, and easy to implement.

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS).

든 샘플 준비 : 울트라 씬 레이어 방법

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption ...

연구

생물학

Quantification of Proteins Using Peptide Immunoaffinity Enrichment Coupled with Mass Spectrometry

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in quantitation, are associated with a high cost, long lead time, and are fraught with drawbacks (e.g. heterophilic antibodies, autoantibody interference, 'hook-effect').1 An alternative technique is affinity enrichment of peptides coupled with quantitative mass spectrometry, commonly referred to as SISCAPA (Stable Isotope Standards and Capture by Anti-Peptide Antibodies).2 In this technique, affinity enrichment of peptides with stable isotope dilution and detection by selected/multiple reaction monitoring mass spectrometry (SRM/MRM-MS) provides quantitative measurement of peptides as surrogates for their respective proteins. SRM/MRM-MS is well established for accurate quantitation of small molecules 3, 4 and more recently has been adapted to measure the concentrations of proteins in plasma and cell lysates.5-7 To achieve quantitation of proteins, these larger molecules are digested to component peptides using an enzyme such as trypsin. One or more selected peptides whose sequence is unique to the target protein in that species (i.e. "proteotypic" peptides) are then enriched from the sample using anti-peptide antibodies and measured as quantitative stoichiometric surrogates for protein concentration in the sample. Hence, coupled to stable isotope dilution (SID) methods (i.e. a spiked-in stable isotope labeled peptide standard), SRM/MRM can be used to measure concentrations of proteotypic peptides as surrogates for quantification of proteins in complex biological matrices. The assays have several advantages compared to traditional immunoassays. The reagents are relatively less expensive to generate, the specificity for the analyte is excellent, the assays can be highly multiplexed, enrichment can be performed from neat plasma (no depletion required), and the technique is amenable to a wide array of proteins or modifications of interest.8-13 In this video we demonstrate the basic protocol as adapted to a magnetic bead platform.

Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA) couples affinity enrichment of peptides with stable isotope dilution mass spectrometry (MRM-MS) to provide quantitative measurement of peptides as surrogates for their respective proteins. Here we describe the protocol using magnetic particles in a partially automated format.

펩타이드 면역 친 화성 농축을 사용하여 단백질의 양을 정함은 질량 분광법과 함께

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in ...

Amide Hydrogen/Deuterium Exchange &amp; MALDI-TOF Mass Spectrometry Analysis of Pak2 Activation

Amide hydrogen/deuterium exchange (H/D exchange) coupled with mass spectrometry has been widely used to analyze the interface of protein-protein interactions, protein conformational changes, protein dynamics and protein-ligand interactions. H/D exchange on the backbone amide positions has been utilized to measure the deuteration rates of the micro-regions in a protein by mass spectrometry1,2,3. The resolution of this method depends on pepsin digestion of the deuterated protein of interest into peptides that normally range from 3-20 residues. Although the resolution of H/D exchange measured by mass spectrometry is lower than the single residue resolution measured by the Heteronuclear Single Quantum Coherence (HSQC) method of NMR, the mass spectrometry measurement in H/D exchange is not restricted by the size of the protein4. H/D exchange is carried out in an aqueous solution which maintains protein conformation. We provide a method that utilizes the MALDI-TOF for detection2, instead of a HPLC/ESI (electrospray ionization)-MS system5,6. The MALDI-TOF provides accurate mass intensity data for the peptides of the digested protein, in this case protein kinase Pak2 (also called &gamma;-Pak). Proteolysis of Pak 2 is carried out in an offline pepsin digestion. This alternative method, when the user does not have access to a HPLC and pepsin column connected to mass spectrometry, or when the pepsin column on HPLC does not result in an optimal digestion map, for example, the heavily disulfide-bonded secreted Phospholipase A2 (sPLA2). Utilizing this method, we successfully monitored changes in the deuteration level during activation of Pak2 by caspase 3 cleavage and autophosphorylation7,8,9.

MALDI-TOF mass spectrometry was successfully utilized to monitor the amide hydrogen/deuterium exchange in protein kinase Pak2 activation.

Pak2 활성화의 아미드 수소 / 중수소 교환 및 든 - TOF 질량 분광법 분석

Amide hydrogen/deuterium exchange (H/D exchange) coupled with mass spectrometry has been widely used to analyze the interface of protein-protein ...

A Fluorescence-based Exonuclease Assay to Characterize DmWRNexo, Orthologue of Human Progeroid WRN Exonuclease, and Its Application to Other Nucleases

WRN exonuclease is involved in resolving DNA damage that occurs either during DNA replication or following exposure to endogenous or exogenous genotoxins. It is likely to play a role in preventing accumulation of recombinogenic intermediates that would otherwise accumulate at transiently stalled replication forks, consistent with a hyper-recombinant phenotype of cells lacking WRN. In humans, the exonuclease domain comprises an N-terminal portion of a much larger protein that also possesses helicase activity, together with additional sites important for DNA and protein interaction. By contrast, in Drosophila, the exonuclease activity of WRN (DmWRNexo) is encoded by a distinct genetic locus from the presumptive helicase, allowing biochemical (and genetic) dissection of the role of the exonuclease activity in genome stability mechanisms. Here, we demonstrate a fluorescent method to determine WRN exonuclease activity using purified recombinant DmWRNexo and end-labeled fluorescent oligonucleotides. This system allows greater reproducibility than radioactive assays as the substrate oligonucleotides remain stable for months, and provides a safer and relatively rapid method for detailed analysis of nuclease activity, permitting determination of nuclease polarity, processivity, and substrate preferences.

Exonucleases play critical roles in ensuring genome stability. Loss of WRN exonuclease function results in premature aging. Studying substrates and other requirements of the nuclease in vitro can help elucidate its role in vivo. Here we demonstrate a rapid and reproducible fluorescence-based assay to measure its nuclease activity.

WRN exonuclease is involved in resolving DNA damage that occurs either during DNA replication or following exposure to endogenous or exogenous genotoxins. ...

Capture Compound Mass Spectrometry - A Powerful Tool to Identify Novel c-di-GMP Effector Proteins

Considerable progress has been made during the last decade towards the identification and characterization of enzymes involved in the synthesis (diguanylate cyclases) and degradation (phosphodiesterases) of the second messenger c-di-GMP. In contrast, little information is available regarding the molecular mechanisms and cellular components through which this signaling molecule regulates a diverse range of cellular processes. Most of the known effector proteins belong to the PilZ family or are degenerated diguanylate cyclases or phosphodiesterases that have given up on catalysis and have adopted effector function. Thus, to better define the cellular c-di-GMP network in a wide range of bacteria experimental methods are required to identify and validate novel effectors for which reliable in silico predictions fail.
We have recently developed a novel Capture Compound Mass Spectrometry (CCMS) based technology as a powerful tool to biochemically identify and characterize c-di-GMP binding proteins. This technique has previously been reported to be applicable to a wide range of organisms1. Here we give a detailed description of the protocol that we utilize to probe such signaling components. As an example, we use Pseudomonas aeruginosa, an opportunistic pathogen in which c-di-GMP plays a critical role in virulence and biofilm control. CCMS identified 74% (38/51) of the known or predicted components of the c-di-GMP network. This study explains the CCMS procedure in detail, and establishes it as a powerful and versatile tool to identify novel components involved in small molecule signaling.

The ubiquitous second messenger c-di-GMP controls growth and behavior of many bacteria. We have developed a novel Capture Compound Mass Spectrometry based technology to biochemically identify and characterize c-di-GMP binding proteins in virtually any bacterial species.

캡처 복합 질량 분석 - 소설의 C 디 GMP 이펙터 단백질을 식별 할 수있는 강력한 도구

Considerable progress has been made during the last decade towards the identification and characterization of enzymes involved in the synthesis ...

Using Digital Image Correlation to Characterize Local Strains on Vascular Tissue Specimens

Characterization of the mechanical behavior of biological and engineered soft tissues is a central component of fundamental biomedical research and product development. Stress-strain relationships are typically obtained from mechanical testing data to enable comparative assessment among samples and in some cases identification of constitutive mechanical properties. However, errors may be introduced through the use of average strain measures, as significant heterogeneity in the strain field may result from geometrical non-uniformity of the sample and stress concentrations induced by mounting/gripping of soft tissues within the test system. When strain field heterogeneity is significant, accurate assessment of the sample mechanical response requires measurement of local strains. This study demonstrates a novel biomechanical testing protocol for calculating local surface strains using a mechanical testing device coupled with a high resolution camera and a digital image correlation technique. A series of sample surface images are acquired and then analyzed to quantify the local surface strain of a vascular tissue specimen subjected to ramped uniaxial loading. This approach can improve accuracy in experimental vascular biomechanics and has potential for broader use among other native soft tissues, engineered soft tissues, and soft hydrogel/polymeric materials. In the video, we demonstrate how to set up the system components and perform a complete experiment on native vascular tissue.

We describe the use of digital image correlation to characterize the local surface strain field on vascular tissue samples subjected to uniaxial tensile testing. These measurements facilitate precise quantification of the sample mechanical response and the generation of constitutive stress-strain relations.

디지털 이미지의 상관 관계를 사용하면 혈관 조직 표본의 로컬 균주의 특성을

Characterization of the mechanical behavior of biological and engineered soft tissues is a central component of fundamental biomedical research and ...

Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry

Skeletal muscle terminal differentiation starts with the commitment of pluripotent mesodermal precursor cells to myoblasts. These cells have still the ability to proliferate or they can differentiate and fuse into multinucleated myotubes, which maturate further to form myofibers. Skeletal muscle terminal differentiation is orchestrated by the coordinated action of various transcription factors, in particular the members of the Muscle Regulatory Factors or MRFs (MyoD, Myogenin, Myf5, and MRF4), also called the myogenic bHLH transcription factors family. These factors cooperate with chromatin-remodeling complexes within elaborate transcriptional regulatory network to achieve skeletal myogenesis. In this, MyoD is considered the master myogenic transcription factor in triggering muscle terminal differentiation. This notion is strengthened by the ability of MyoD to convert non-muscle cells into skeletal muscle cells. Here we describe an approach used to identify MyoD protein partners in an exhaustive manner in order to elucidate the different factors involved in skeletal muscle terminal differentiation. The long-term aim is to understand the epigenetic mechanisms involved in the regulation of skeletal muscle genes, i.e., MyoD targets. MyoD partners are identified by using Tandem Affinity Purification (TAP-Tag) from a heterologous system coupled to mass spectrometry (MS) characterization, followed by validation of the role of relevant partners during skeletal muscle terminal differentiation. Aberrant forms of myogenic factors, or their aberrant regulation, are associated with a number of muscle disorders: congenital myasthenia, myotonic dystrophy, rhabdomyosarcoma and defects in muscle regeneration. As such, myogenic factors provide a pool of potential therapeutic targets in muscle disorders, both with regard to mechanisms that cause disease itself and regenerative mechanisms that can improve disease treatment. Thus, the detailed understanding of the intermolecular interactions and the genetic programs controlled by the myogenic factors is essential for the rational design of efficient therapies.

MyoD is a myogenic transcription factor with a strong capacity to induce myogenic transdifferentiation of many fully differentiated non-muscle cell lines. The epigenetic mechanisms involved in this transdifferentiation are largely unknown. Here we describe a double-affinity purification method followed by mass spectrometry to exhaustively characterize MyoD partners.

탠덤 선호도 정화를 사용하여 MyoD 상호 작용 체의 식별 질량 분석에 결합

Skeletal muscle terminal differentiation starts with the commitment of pluripotent mesodermal precursor cells to myoblasts. These cells have still the ...

Complete Workflow for Analysis of Histone Post-translational Modifications Using Bottom-up Mass Spectrometry: From Histone Extraction to Data Analysis

Nucleosomes are the smallest structural unit of chromatin, composed of 147 base pairs of DNA wrapped around an octamer of histone proteins. Histone function is mediated by extensive post-translational modification by a myriad of nuclear proteins. These modifications are critical for nuclear integrity as they regulate chromatin structure and recruit enzymes involved in gene regulation, DNA repair and chromosome condensation. Even though a large part of the scientific community adopts antibody-based techniques to characterize histone PTM abundance, these approaches are low throughput and biased against hypermodified proteins, as the epitope might be obstructed by nearby modifications. This protocol describes the use of nano liquid chromatography (nLC) and mass spectrometry (MS) for accurate quantification of histone modifications. This method is designed to characterize a large variety of histone PTMs and the relative abundance of several histone variants within single analyses. In this protocol, histones are derivatized with propionic anhydride followed by digestion with trypsin to generate peptides of 5 - 20 aa in length. After digestion, the newly exposed N-termini of the histone peptides are derivatized to improve chromatographic retention during nLC-MS. This method allows for the relative quantification of histone PTMs spanning four orders of magnitude.

This protocol outlines a fully integrated workflow for characterizing histone post-translational modifications using mass spectrometry (MS). The workflow includes histone purification from cell cultures or tissues, histone derivatization and digestion, MS analysis using nano-flow liquid chromatography and instructions for data analysis. The protocol is designed for completion within 2 - 3 days.

히스톤 추출에서 데이터 분석에 : 상향식 질량 분석 사용 히스톤 번역 후 변형 분석을위한 완벽한 워크 플로우

Nucleosomes are the smallest structural unit of chromatin, composed of 147 base pairs of DNA wrapped around an octamer of histone proteins. Histone ...

At-Risk Butterfly Captive Propagation Programs to Enhance Life History Knowledge and Effective Ex Situ Conservation Techniques

Improving knowledge of ex situ best practices for at-risk butterflies is important for generating successful conservation and recovery program outcomes. Research on such captive populations can also yield valuable data to address key information gaps about the behavior, life history, and ecology of the target taxa. We describe a protocol for captive propagation of the federally endangered Cyclargus thomasi bethunebakeri that can be used as a model for other at-risk butterfly ex situ programs, especially those in the family Lycaenidae. We further provide a simple and straightforward protocol for recording various life history metrics that can be useful for informing ex situ methodologies as well as adapted for laboratory studies of other lepidoptera.

Here, we present protocols for 1) the laboratory captive propagation of the federally endangered Miami blue butterfly (Cyclargus thomasi bethunebakeri), and 2) assessing basic life history information such as immature development time and number of larval stadia. Both methods can be adapted for use with other ex situ conservation programs.

생명역사 지식과 효과적인 Ex Situ 보존 기술을 향상시키기 위한 위험에 처한 나비 포로 전파 프로그램

Improving knowledge of ex situ best practices for at-risk butterflies is important for generating successful conservation and recovery program outcomes. ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.