저자는 이 프로토콜을 개선하는 데 기여한 Jennifer Geddes-McAlister 박사와 Anthony Clarke 박사에게 감사를 표합니다. 이 작업은 C.M.K(PJT 156111)에 수여된 CIHR의 운영 보조금과 E.M.A.에 수여된 NSERC Alexander Graham Bell CGS D의 지원을 받았습니다. 피규어는 BioRender.com 에 만들어졌습니다.

<ol>
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저자는 이해 상충을 선언하지 않습니다.

이 프로토콜은 박테리아 배양에서 펩티도글리칸을 정제하고, LC-MS 검출을 처리하고, 생물정보학 기술을 사용하여 조성을 분석하는 방법을 설명합니다. 여기서는 그람 음성 박테리아에 초점을 맞추고 그람 양성 박테리아를 분석하려면 약간의 수정이 필요합니다.
muropeptides의 제조는 1960 년대 9,11,15 년에 처음 생산 된 이<sup cl...

펩티도글리칸(Peptidoglycan, PG)은 단백질 및 기타 세포 성분에 대한 구조적 지지를 제공하면서 세포 형태를 유지하는 역할을 하는 박테리아의 특징이다 1,2. PG의 백본은 교대로 β-1,4-연결된 N-아세틸 무라믹산(MurNAc)과 N-아세틸 글루코사민(GlcNAc)1,2로 구성됩니다. 각 MurNAc는 인접한 이당류 결합 펩타이드에 가교될 수 있는 ᴅ-락틸 잔기에 결합된 짧은 펩타이드를 가지고 있습니다(그림 1A, B). 이 가교결합은 전체 세포를 둘러싸고 있는 그물망과 같은 구조를 생성하며 종종 천골이라고 합니다(그림 1C). PG 합성 동안, 전구체는 세포질에서 생성되고, 플리파스에 의해 세포질 막을 가로질러 운반된다. 전구체는 후속적으로 트랜스글리코실라제와 트랜스펩티다아제 효소에 의해 성숙한 PG에 혼입되며, 이는 각각 글리코시드 및 펩티드 결합을 생성한다3. 그러나 일단 조립되면 성장 및 분열을 포함한 여러 세포 과정을 수행하기 위해 PG를 수정 및/또는 분해하는 박테리아에 의해 생성되는 수많은 효소가 있습니다. 또한, PG의 다양한 변형은 균주, 성장 조건 및 환경 스트레스에 특이적인 적응을 부여하는 것으로 나타났으며, 이는 세포 신호 전달, 항생제 내성 및 숙주 면역 회피와 관련이 있다4. 예를 들어, 일반적인 변형은 PG 4,5,6을 분해하는 숙주 생산 리소자임 효소에 대한 글리칸 β-1,4 결합에 대한 접근을 제한함으로써 저항성을 부여하는 MurNAc에 C6 아세틸기를 추가하는 것입니다. 장구균에서 펩타이드 측쇄의 말단 ᴅ-Ala를 ᴅ-Lac로 치환하면 항균제인 반코마이신 7,8에 대한 내성이 더 커집니다.
PG 분리 및 정제를 위한 일반적인 절차는 1960년대에 기술된 이래로 비교적 변하지 않았다9. 박테리아 막은 SDS로 열처리를 통해 용해된 후 결합된 단백질, 당지질 및 나머지 DNA를 효소로 제거합니다. 정제된 온전한 천골은 GlcNAc와 MurNAc 사이의 β-1,4 결합의 가수분해에 의해 개별 성분으로 후속적으로 분해될 수 있습니다. 이 소화는 구조적 변형 및/또는 가교결합이 손상되지 않은 GlcNAc-MurNAc 이당류를 생성하며 이를 무로펩티드라고 합니다(그림 1B).
PG의 조성 분석은 초기에 고압 액체 크로마토그래피 분리(HPLC)를 통해 수행되어 각 무로펩티드를 정제한 후 무로펩티드10,11을 수동으로 식별했습니다. 이는 이후 액체 크로마토그래피 탠덤 질량분석법(LC-MS)으로 대체되어 검출 감도를 높이고 각 개별 무로펩타이드를 정제하는 수동 작업량을 줄입니다. 그러나 muropeptides의 수동 식별의 시간 소모적이고 복잡한 특성은 여전히 제한 요소로 남아 수행된 연구의 수를 줄입니다. 최근 몇 년 동안 "omic" 기술의 출현으로 자동화된 LC-MS 특징 추출이 강력한 도구가 되어 매우 큰 데이터 세트의 복잡한 샘플에서 개별 화합물을 신속하게 검출하고 식별할 수 있습니다. 특징이 식별되면 생물정보학 소프트웨어는 복잡한 데이터 세트 간의 최소한의 차이도 분리하여 사용자에게 그래픽으로 표시하는 차등 분석을 사용하여 샘플 간의 변동을 통계적으로 비교합니다. PG 조성의 분석을 위한 특징 추출 소프트웨어의 적용은 이제 막 탐구되기 시작했고(12,13,14) 생물정보 학적 분석(bioinformatic analysis)12과 결합되었다. 펩타이드 단편화를 예측하여 완전히 자동화된 식별을 가능하게 하는 쉽게 사용할 수 있는 단백질 데이터베이스의 이점을 제공하는 단백질체 분석과 달리 현재 펩티도글리코믹스에 대한 단편화 라이브러리는 존재하지 않습니다. 그러나, 특징 추출은 무로펩티드 식별을 예측하기 위해 알려지고 예측된 구조 데이터베이스와 결합될 수 있다12. 여기에서는 PG 조성의 자동 식별 및 생물정보학적 차등 분석을 위해 무로펩타이드 라이브러리와 결합된 LC-MS 기반 특징 추출의 사용에 대한 자세한 프로토콜을 제시합니다(그림 2).

<table>
	<tbody>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>C18 reverse phase column - AdvanceBio Peptide column (100 mm x 2.1 mm 2.7 &#181;m)</td>
			<td>Agilent</td>
			<td></td>
			<td>LC-MS data acquisition</td>
		</tr>
		<tr>
			<td>Heating mantle controller, Optichem</td>
			<td>Fisher</td>
			<td>50-401-788</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>Heating Mantle, 1000mL Hemispherical</td>
			<td>Fisher</td>
			<td>CG1000008</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>Incubator, 37&#176;C</td>
			<td></td>
			<td></td>
			<td>for sacculi purification and MS sample prep</td>
		</tr>
		<tr>
			<td>Leibig condenser, 300MM 24/40,</td>
			<td>Fisher</td>
			<td>CG121805</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>Lyophilizer</td>
			<td>Labconco</td>
			<td></td>
			<td>for lyophilization of sacculi</td>
		</tr>
		<tr>
			<td>Magentic stirrer</td>
			<td>Fisher</td>
			<td>90-691-18</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>mass spectrometer Q-Tof model UHD 6530</td>
			<td>Aglient</td>
			<td></td>
			<td>LC-MS data acquisition</td>
		</tr>
		<tr>
			<td>microcentrifuge filters, Nanosep MF 0.2 &#181;m</td>
			<td>Fisher</td>
			<td>50-197-9573</td>
			<td>cleanup of sample before MS injection</td>
		</tr>
		<tr>
			<td>Retort stand</td>
			<td>Fisher</td>
			<td>12-000-102</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>Retort clamp</td>
			<td>Fisher</td>
			<td>S02629</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>round bottom flask - 1 liter pyrex</td>
			<td>Fisher</td>
			<td>07-250-084</td>
			<td>for 4% SDS boil</td>
		</tr>
		<tr>
			<td>Sonicator model 120</td>
			<td>Fisher</td>
			<td>FB120</td>
			<td>for sacculi purification</td>
		</tr>
		<tr>
			<td>Sonicator - micro tip</td>
			<td>Fisher</td>
			<td>FB4422</td>
			<td>for sacculi purification</td>
		</tr>
		<tr>
			<td>Ultracentrifuge</td>
			<td>Beckman</td>
			<td></td>
			<td>sacculi wash steps</td>
		</tr>
		<tr>
			<td>Ultracentrifuge bottles, Ti45</td>
			<td>Fisher</td>
			<td>NC9691797</td>
			<td>sacculi wash steps</td>
		</tr>
		<tr>
			<td>Water supply</td>
			<td>City</td>
			<td></td>
			<td>for water cooled condenser</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Chemdraw</td>
			<td>Cambridgesoft</td>
			<td></td>
			<td>molecular editor for muropeptide fragmentation prediction</td>
		</tr>
		<tr>
			<td>Excel</td>
			<td>Microsoft</td>
			<td></td>
			<td>viewing lists of annotated muropeptides, abundance, isotopic patterns, etc.</td>
		</tr>
		<tr>
			<td>MassHunter Acquisition</td>
			<td>Aglient</td>
			<td></td>
			<td>running QTOF instrument</td>
		</tr>
		<tr>
			<td>MassHunter Mass Profiler Professional</td>
			<td>Aglient</td>
			<td></td>
			<td>bioinformatic differential analysis</td>
		</tr>
		<tr>
			<td>MassHunter Personal Compound Database and Library Manager</td>
			<td>Aglient</td>
			<td></td>
			<td>muropeptide m/z MS database</td>
		</tr>
		<tr>
			<td>MassHunter Profinder</td>
			<td>Aglient</td>
			<td></td>
			<td>recursive feature extraction</td>
		</tr>
		<tr>
			<td>MassHunter Qualitative analysis</td>
			<td>Aglient</td>
			<td></td>
			<td>viewing MS and MS/MS chromatograms</td>
		</tr>
		<tr>
			<td>Prism</td>
			<td>Graphpad</td>
			<td></td>
			<td>Graphing software</td>
		</tr>
		<tr>
			<td>Perseus</td>
			<td>Max Plank Institute of Biochemistry</td>
			<td></td>
			<td>1D annotation</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Acetonitrile</td>
			<td>Fisher</td>
			<td>A998-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium acetate</td>
			<td>Fisher</td>
			<td>A637</td>
			<td></td>
		</tr>
		<tr>
			<td>Amylase</td>
			<td>Sigma-Aldrich</td>
			<td>A6380</td>
			<td></td>
		</tr>
		<tr>
			<td>Boric acid</td>
			<td>Fisher</td>
			<td>BP168-1</td>
			<td></td>
		</tr>
		<tr>
			<td>DNase</td>
			<td>Fisher</td>
			<td>EN0521</td>
			<td></td>
		</tr>
		<tr>
			<td>Formic acid</td>
			<td>Sigma-Aldrich</td>
			<td>27001-500ML-R</td>
			<td></td>
		</tr>
		<tr>
			<td>LC-MS tuning mix - HP0321</td>
			<td>Agilent</td>
			<td>G1969-85000</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium chloride</td>
			<td>Sigma-Aldrich</td>
			<td>M8266</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium sulfate</td>
			<td>Sigma-Aldrich</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr>
			<td>Mutanolysin from Streptomyces globisporus ATCC 21553</td>
			<td>Sigma-Aldrich</td>
			<td>M9901</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrogen gas (&#62;99% purity)</td>
			<td>Praxair</td>
			<td>NI 5.0UH-T</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphoric acid</td>
			<td>Fisher</td>
			<td>A242</td>
			<td></td>
		</tr>
		<tr>
			<td>Pronase E from Streptomyces griseus</td>
			<td>Sigma-Aldrich</td>
			<td>P5147</td>
			<td></td>
		</tr>
		<tr>
			<td>RNase</td>
			<td>Fisher</td>
			<td>EN0531</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium azide</td>
			<td>Fisher</td>
			<td>S0489</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium borohydride</td>
			<td>Sigma-Aldrich</td>
			<td>452890</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dodecyl sulfate (SDS)</td>
			<td>Fisher</td>
			<td>BP166</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Fisher</td>
			<td>S318</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Phosphate (dibasic)</td>
			<td>Fisher</td>
			<td>S373</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Phosphate (monobasic)</td>
			<td>Fisher</td>
			<td>S369</td>
			<td></td>
		</tr>
		<tr>
			<td>Stains-all</td>
			<td>Sigma-Aldrich</td>
			<td>E9379</td>
			<td></td>
		</tr>
	</tbody>
</table>

semi-quantitative analysis of peptidoglycan by liquid chromatography mass spectrometry and bioinformatics

펩티도글리칸은 박테리아 세포벽의 중요한 구성 요소이며 항균제의 일반적인 세포 표적입니다. 펩티도글리칸 구조의 측면은 모든 박테리아에 걸쳐 상당히 보존되어 있지만 그람 양성/음성 및 종 간에도 상당한 차이가 있습니다. 또한, 성장 단계 및/또는 환경 자극에 대한 반응으로 박테리아 종 내에서 발생할 수 있는 펩티도글리칸에 대한 수많은 알려진 변이, 변형 또는 적응이 있습니다. 이러한 변이는 성장/분열, 항생제 내성 및 숙주 방어 회피를 포함한 많은 세포 기능에 참여하는 것으로 알려진 매우 역동적인 구조를 생성합니다. 펩티도글리칸 내의 변이를 이해하려면 전체 구조를 구성 부분(무로펩티드로 알려짐)으로 분해하고 전체 세포 구성에 대해 평가해야 합니다. Peptidoglycomics는 고성능 생물정보학 데이터 분석과 결합된 고급 질량분석법을 사용하여 펩티도글리칸 조성을 세밀하게 조사합니다. 다음 프로토콜은 박테리아 배양에서 펩티도글리칸의 정제, 액체 크로마토그래프(질량 분석기)를 통한 무로펩티드 강도 데이터 획득, 생물정보학을 사용한 펩티도글리칸 조성의 차등 분석에 대해 설명합니다.

고성능 피크 인식 소프트웨어와 결합된 MS 기계의 향상된 검출 감도는 복잡한 샘플의 물질 조성을 매우 세밀하게 분리, 모니터링 및 분석하는 기능을 향상시켰습니다. 이러한 기술적 진보를 이용하여, 펩티도글리칸 조성물에 대한 최근 연구들은 이전의 HPLC-기반 방법론 11,25,26,27,28,29,30,31에 비해 자동화된 LC-MS 특징 추출 기술12,13,14,24<s...

Watch this Scientific Journal Video about Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics at JoVE.com

Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

이 프로토콜은 고급 특징 추출 및 생물정보학 분석 소프트웨어와 결합된 액체 크로마토그래피 질량분석법을 사용하여 펩티도글리칸 조성에 대한 자세한 분석을 다룹니다.

액체 크로마토그래피, 질량 분석법 및 생물정보학에 의한 펩티도글리칸의 반정량 분석

Peptidoglycan is an important component of bacterial cell walls and a common cellular target for antimicrobials. Although aspects of peptidoglycan ...

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Biochemistry

4.1K 조회수.  University of Guelph. 이 프로토콜은 고급 특징 추출 및 생물정보학 분석 소프트웨어와 결합된 액체 크로마토그래피 질량분석법을 사용하여 펩티도글리칸 조성에 대한 자세한 분석을 다룹니다.

비디오: Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

Time-resolved ElectroSpray Ionization Hydrogen-deuterium Exchange Mass Spectrometry for Studying Protein Structure and Dynamics

Intrinsically disordered proteins (IDPs) have long been a challenge to structural biologists due to their lack of stable secondary structure elements. Hydrogen-Deuterium Exchange (HDX) measured at rapid time scales is uniquely suited to detect structures and hydrogen bonding networks that are briefly populated, allowing for the characterization of transient conformers in native ensembles. Coupling of HDX to mass spectrometry offers several key advantages, including high sensitivity, low sample consumption and no restriction on protein size. This technique has advanced greatly in the last several decades, including the ability to monitor HDX labeling times on the millisecond time scale. In addition, by incorporating the HDX workflow onto a microfluidic platform housing an acidic protease microreactor, we are able to localize dynamic properties at the peptide level. In this study, Time-Resolved ElectroSpray Ionization Mass Spectrometry (TRESI-MS) coupled to HDX was used to provide a detailed picture of residual structure in the tau protein, as well as the conformational shifts induced upon hyperphosphorylation.

Conformational flexibility plays a critical role in protein function. Herein, we describe the use of time-resolved electrospray ionization mass spectrometry coupled to hydrogen-deuterium exchange for probing the rapid structural changes that drive function in ordered and disordered proteins.

시간 해결 전기 분무 이온화 수소 - 중수소 교환 질량 분석 단백질 구조와 역학 연구를위한

Intrinsically disordered proteins (IDPs) have long been a challenge to structural biologists due to their lack of stable secondary structure elements. ...

연구

생화학

Resolving Affinity Purified Protein Complexes by Blue Native PAGE and Protein Correlation Profiling

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological processes. Affinity purification coupled to mass spectrometry (AP-MS) has become the method of choice for identifying protein-protein interactions. However, conventional AP-MS studies provide information on protein interactions, but the organizational information is lost. To address this issue, we developed a strategy to unravel the distinct functional assemblies a protein might be involved in, by resolving affinity-purified protein complexes prior to their characterization by mass spectrometry. Protein complexes isolated through affinity purification of a bait protein using an epitope tag and competitive elution are separated through blue native electrophoresis. Comparison of protein migration profiles through correlation profiling using quantitative mass spectrometry allows assignment of interacting proteins to distinct molecular entities. This method is able to resolve protein complexes of close molecular weights that might not be resolved by traditional chromatographic techniques such as gel filtration. With little more work than conventional AP-geLC-MS/MS, we demonstrate this strategy may in many cases be adequate for obtaining protein complex topological information concomitantly to identifying protein interactions.

Here we present protocols for affinity purification of protein complexes and their separation by blue native PAGE, followed by protein correlation profiling using label free quantitative mass spectrometry. This method is useful to resolve interactomes into distinct protein complexes.

블루 기본 페이지와 단백질 상관 관계 프로파일 링에 의한 선호도 정제 단백질 복합체 해결

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological ...

A Tandem Liquid Chromatography&#8211;Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus

In an effort to thwart bacterial pathogens, hosts often limit the availability of nutrients at the site of infection. This limitation can alter the abundances of key metabolites to which regulatory factors respond, adjusting cellular metabolism. In recent years, a number of proteins and RNA have emerged as important regulators of virulence gene expression. For example, the CodY protein responds to levels of branched-chain amino acids and GTP and is widely conserved in low G+C Gram-positive bacteria. As a global regulator in Staphylococcus aureus, CodY controls the expression of dozens of virulence and metabolic genes. We hypothesize that S. aureus uses CodY, in part, to alter its metabolic state in an effort to adapt to nutrient-limiting conditions potentially encountered in the host environment. This manuscript describes a method for extracting and analyzing metabolites from S. aureus using liquid chromatography coupled with mass spectrometry, a protocol that was developed to test this hypothesis. The method also highlights best practices that will ensure rigor and reproducibility, such as maintaining biological steady state and constant aeration without the use of continuous chemostat cultures. Relative to the USA200 methicillin-susceptible S. aureus isolate UAMS-1 parental strain, the isogenic codY mutant exhibited significant increases in amino acids derived from aspartate (e.g., threonine and isoleucine) and decreases in their precursors (e.g., aspartate and O-acetylhomoserine). These findings correlate well with transcriptional data obtained with RNA-seq analysis: genes in these pathways were up-regulated between 10- and 800-fold in the codY null mutant. Coupling global analyses of the transcriptome and the metabolome can reveal how bacteria alter their metabolism when faced with environmental or nutritional stress, providing potential insight into the physiological changes associated with nutrient depletion experienced during infection. Such discoveries may pave the way for the development of novel anti-infectives and therapeutics.

A Tandem Liquid Chromatography&amp;#8211;Mass Spectrometry-based Approach for Metabolite Analysis of &lt;em&gt;Staphylococcus aureus&lt;/em&gt;

Here we describe a protocol for the extraction of metabolites from Staphylococcus aureus and their subsequent analysis via liquid chromatography and mass spectrometry.

의 대사 산물 분석을위한 탠덤 액체 크로마토 그래피 - 질량 분석 기반 접근<em&gt; 포도상 구균</em

In an effort to thwart bacterial pathogens, hosts often limit the availability of nutrients at the site of infection. This limitation can alter the ...

Lipid Droplet Isolation for Quantitative Mass Spectrometry Analysis

Lipid droplets are vital to the replication of a variety of different pathogens, most prominently the Hepatitis C Virus (HCV), as the putative site of virion morphogenesis. Quantitative lipid droplet proteome analysis can be used to identify proteins that localize to or are displaced from lipid droplets under conditions such as virus infections. Here, we describe a protocol that has been successfully used to characterize the changes in the lipid droplet proteome following infection with HCV. We use Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) and thus label the complete proteome of one population of cells with &#34;heavy&#34; amino acids to quantitate the proteins by mass spectrometry. For lipid droplet isolation, the two cell populations (i.e.&#160;HCV-infected/&#34;light&#34; amino acids and uninfected control/&#34;heavy&#34; amino acids) are mixed 1:1 and lysed mechanically in hypotonic buffer. After removing the nuclei and cell debris by low speed centrifugation, lipid droplet-associated proteins are enriched by two subsequent ultracentrifugation steps followed by three washing steps in isotonic buffer. The purity of the lipid droplet fractions is analyzed by western blotting with antibodies recognizing different subcellular compartments. Lipid droplet-associated proteins are then separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Coomassie staining. After tryptic digest, the peptides are quantified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Using this method, we identified proteins recruited to lipid droplets upon HCV infection that might represent pro- or antiviral host factors. Our method can be applied to a variety of different cells and culture conditions, such as infection with pathogens, environmental stress, or drug treatment.

Lipid droplets are important organelles for the replication of several pathogens, including the Hepatitis C Virus (HCV). We describe a method to isolate lipid droplets for quantitative mass spectrometry of associated proteins; it can be used under a variety of conditions, such as virus infection, environmental stress, or drug treatment.

양적 질량 분광법 분석을위한 지질 물방울 절연

Lipid droplets are vital to the replication of a variety of different pathogens, most prominently the Hepatitis C Virus (HCV), as the putative site of ...

Deep Proteome Profiling by Isobaric Labeling, Extensive Liquid Chromatography, Mass Spectrometry, and Software-assisted Quantification

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) coupled to tandem mass spectrometry (LC-MS/MS) and isobaric labeling multiplexing capacity. Here, we introduce a deep-proteomics profiling protocol that combines 10-plex tandem mass tag (TMT) labeling with an extensive LC/LC-MS/MS platform, and post-MS computational interference correction to accurately quantitate whole proteomes. This protocol includes the following main steps: protein extraction and digestion, TMT labeling, 2-dimensional (2D) LC, high-resolution mass spectrometry, and computational data processing. Quality control steps are included for troubleshooting and evaluating experimental variation. More than 10,000 proteins in mammalian samples can be confidently quantitated with this protocol. This protocol can also be applied to the quantitation of post translational modifications with minor changes. This multiplexed, robust method provides a powerful tool for proteomic analysis in a variety of complex samples, including cell culture, animal tissues, and human clinical specimens.

We present a protocol to accurately quantitate proteins with isobaric labelling, extensive fractionation, bioinformatics tools, and quality control steps in combination with liquid chromatography interfaced to a high-resolution mass spectrometer.

깊은 프로테옴 Isobaric 라벨, 광범위 한 액체 크로마토그래피, 질량 분석 및 소프트웨어 기반 정량화 하 여 프로 파일링

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) ...

Detection of Protein Ubiquitination Sites by Peptide Enrichment and Mass Spectrometry

The posttranslational modification of proteins by the small protein ubiquitin is involved in many cellular events. After tryptic digestion of ubiquitinated proteins, peptides with a diglycine remnant conjugated to the epsilon amino group of lysine (&#39;K-&#949;-diglycine&#39; or simply &#39;diGly&#39;) can be used to track back the original modification site. Efficient immunopurification of diGly peptides combined with sensitive detection by mass spectrometry has resulted in a huge increase in the number of ubiquitination sites identified up to date. We have made several improvements to this workflow, including offline high pH reverse-phase fractionation of peptides prior to the enrichment procedure, and the inclusion of more advanced peptide fragmentation settings in the ion routing multipole. Also, more efficient cleanup of the sample using a filter-based plug in order to retain the antibody beads results in a greater specificity for diGly peptides. These improvements result in the routine detection of more than 23,000 diGly peptides from human cervical cancer cells (HeLa) cell lysates upon proteasome inhibition in the cell. We show the efficacy of this strategy for in-depth analysis of the ubiquitinome profiles of several different cell types and of in vivo samples, such as brain tissue. This study presents an original addition to the toolbox for protein ubiquitination analysis to uncover the deep cellular ubiquitinome.

We present a method for the purification, detection, and identification of diGly peptides that originate from ubiquitinated proteins from complex biological samples. The presented method is reproducible, robust, and outperforms published methods with respect to the level of depth of the ubiquitinome analysis.

펩타이드 농축 및 질량 분광법에 의한 단백질 유비퀴틴화 부위 검출

The posttranslational modification of proteins by the small protein ubiquitin is involved in many cellular events. After tryptic digestion of ...

Nitropeptide Profiling and Identification Illustrated by Angiotensin II

Protein nitration is one of the most important post-translational modifications (PTM) on tyrosine residues and it can be induced by chemical actions of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in eukaryotic cells. Precise identification of nitration sites on proteins is crucial for understanding the physiological and pathological processes related to protein nitration, such as inflammation, aging, and cancer. Since the nitrated proteins are of low abundance in cells even under induced conditions, no universal and efficient methods have been developed for the profiling and identification of protein nitration sites. Here we describe a protocol for nitropeptide enrichment by using a chemical reduction reaction and biotin labeling, followed by high resolution mass spectrometry. In our method, nitropeptide derivatives can be identified with high accuracy. Our method exhibits two advantages compared to the previously reported methods. First, dimethyl labeling is used to block the primary amine on nitropeptides, which can be used to generate quantitative results. Second, a disulfide bond containing NHS-biotin reagent is used for the enrichment, which can be further reduced and alkylated to enhance the detection signal on a mass spectrometer. This protocol has been successfully applied to the model peptide Angiotensin II in the current paper.

Proteomic profiling of tyrosine-nitrated proteins has been a challenging technique due to the low abundance of the 3-nitrotyrosine modification. Here we describe a novel approach for nitropeptide enrichment and profiling by using Angiotensin II as the model. This method can be extended for other in vitro or in vivo systems.

안지오텐신 II에 의해 설명 니트로 펩티드 프로파일링 및 식별

Protein nitration is one of the most important post-translational modifications (PTM) on tyrosine residues and it can be induced by chemical actions of ...

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Inositol phosphates and phosphoinositides regulate several cellular processes in eukaryotes, including gene expression, vesicle trafficking, signal transduction, metabolism, and development. These metabolites perform this regulatory activity by binding to proteins, thereby changing protein conformation, catalytic activity, and/or interactions. The method described here uses affinity chromatography coupled to mass spectrometry or Western blotting to identify proteins that interact with inositol phosphates or phosphoinositides. Inositol phosphates or phosphoinositides are chemically tagged with biotin, which is then captured via streptavidin conjugated to agarose or magnetic beads. Proteins are isolated by their affinity of binding to the metabolite, then eluted and identified by mass spectrometry or Western blotting. The method has a simple workflow that is sensitive, non-radioactive, liposome-free, and customizable, supporting the analysis of protein and metabolite interaction with precision. This approach can be used in label-free or in amino acid-labelled quantitative mass spectrometry methods to identify protein-metabolite interactions in complex biological samples or using purified proteins. This protocol is optimized for the analysis of proteins from Trypanosoma brucei, but it can be adapted to related protozoan parasites, yeast or mammalian cells.

This protocol focuses on the identification of proteins that bind to inositol phosphates or phosphoinositides. It uses affinity chromatography with biotinylated inositol phosphates or phosphoinositides that are immobilized via streptavidin to agarose or magnetic beads. Inositol phosphate or phosphoinositide binding proteins are identified by Western blotting or mass spectrometry.

이노시톨 인산염 또는 인산성교단백질의 동정은 서부 블롯 또는 질량분광법에 결합된 친화성 크로마토그래피에 의한 단백질

Inositol phosphates and phosphoinositides regulate several cellular processes in eukaryotes, including gene expression, vesicle trafficking, signal ...

Absolute Quantification of Cell-Free Protein Synthesis Metabolism by Reversed-Phase Liquid Chromatography-Mass Spectrometry

Cell-free protein synthesis (CFPS) is an emerging technology in systems and synthetic biology for the in vitro production of proteins. However, if CFPS is going to move beyond the laboratory and become a widespread and standard just in time manufacturing technology, we must understand the performance limits of these systems. Toward this question, we developed a robust protocol to quantify 40 compounds involved in glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle, energy metabolism and cofactor regeneration in CFPS reactions. The method uses internal standards tagged with 13C-aniline, while compounds in the sample are derivatized with 12C-aniline. The internal standards and sample were mixed and analyzed by reversed-phase liquid chromatography-mass spectrometry (LC/MS). The co-elution of compounds eliminated ion suppression, allowing the accurate quantification of metabolite concentrations over 2-3 orders of magnitude where the average correlation coefficient was 0.988. Five of the forty compounds were untagged with aniline, however, they were still detected in the CFPS sample and quantified with a standard curve method. The chromatographic run takes approximately 10 min to complete. Taken together, we developed a fast, robust method to separate and accurately quantify 40 compounds involved in CFPS in a single LC/MS run. The method is a comprehensive and accurate approach to characterize cell-free metabolism, so that ultimately, we can understand and improve the yield, productivity and energy efficiency of cell-free systems.

Here, we present a robust protocol to quantify 40 compounds involved in central carbon and energy metabolism in cell-free protein synthesis reactions. The cell-free synthesis mixture is derivatized with aniline for effective separation using reversed-phase liquid chromatography and then quantified by mass spectrometry using isotopically labelled internal standards.

역상 액체 크로마토그래피-질량 분광법에 의한 무세포 단백질 합성 대사의 절대 정량화

Cell-free protein synthesis (CFPS) is an emerging technology in systems and synthetic biology for the in vitro production of proteins. However, if CFPS is ...

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of biological membranes, energy storage and production, cellular signaling, vesicular transport of proteins, organelle biogenesis, and regulated cell death. Because the budding yeast Saccharomyces cerevisiae is a unicellular eukaryote amenable to thorough molecular analyses, its use as a model organism helped uncover mechanisms linking lipid metabolism and intracellular transport to complex biological processes within eukaryotic cells. The availability of a versatile analytical method for the robust, sensitive, and accurate quantitative assessment of major classes of lipids within a yeast cell is crucial for getting deep insights into these mechanisms. Here we present a protocol to use liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the quantitative analysis of major cellular lipids of S. cerevisiae. The LC-MS/MS method described is versatile and robust. It enables the identification and quantification of numerous species (including different isobaric or isomeric forms) within each of the 10 lipid classes. This method is sensitive and allows identification and quantitation of some lipid species at concentrations as low as 0.2 pmol/&#181;L. The method has been successfully applied to assessing lipidomes of whole yeast cells and their purified organelles. The use of alternative mobile phase additives for electrospray ionization mass spectrometry in this method can increase the efficiency of ionization for some lipid species and can be therefore used to improve their identification and quantitation.

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

We present a protocol using liquid chromatography coupled with tandem mass spectrometry to identify and quantify major cellular lipids in Saccharomyces cerevisiae. The described method for a quantitative assessment of major lipid classes within a yeast cell is versatile, robust, and sensitive.

탠덤 질량 분석과 결합 된 액체 크로마토그래피를 사용하여 사카로 미세화세세비시아의 세포 지질의 정량분석

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of ...