وقد تم تمويل هذا العمل من قبل الخلايا العصبية، ERANET اكتشاف (BMBF 01EW1003) لCK وJPH، DFG (كو 1679/3-1؛ GRK1033) لCKVB معتمد من قبل منحة من Forschungskommission من كلية الطب في جامعة دوسلدورف.

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الإعلان عن أي تضارب في المصالح.

في هذه الدراسة وصفنا عملية تنقية mRFP/eGFP-DISC1 aggresomes من الخلايا العصبية خط بالنقل، إعداد ووضع العلامات من نوع البروتين المؤتلف DISC1 وتطبيقها في الخلية الغزو تجارب الخلايا المتلقية في التجارب المختبرية والحية. وقد تم تطوير عملية تنقية aggresomes mRFP/eGFP-DISC1 الأصلية من البروتوكولات لعزل ليوي الجسم مثل الهياكل وأكبر المجاميع 13 و 14، ولكن تعديل لتجنب استخدام المنظفات وتقليل خطر إيجابية كاذبة الخلية الغزو التي قد تحدث بسبب اختراق الغشاء المنظفات الميسرة. يمكن للمرء تحسين محتملة في المستقبل يكون في لزيادة نقاء aggresomes من صوتنة إلى الأغشية منفصلة تماما المتبقية والهيكل الخلوي من aggresomes. بواسطة نقاء العام زيادة، وعدد من الأحداث التي سجلت إجمالي غزو لأماه aggresomes كبيرةيمكن زيادة Y 5. وينبغي النظر في ما إذا كان تعريف محدود من السكروز لدينا 3-المرحلة اقترح كافية لaggresomes الأنواع الأخرى البروتين لابد من اختبارها، وبهذا المعنى البروتوكول المذكورة هنا كنقطة انطلاق لتعظيم الاستفادة الفردية. أثبتت aggresomes المنقى أن تكون قوية جدا في أيدينا، غسل خطوات إضافية (بدون المنظفات) للقضاء على آثار من السكروز لم تقلل كثيرا من العائد الكلي. في منشور السابقة صفنا هذا التجميع قليل وحدات من DISC1 يعتمد على المجالات multimerization متميزة في محطة سي 4 (الشكل 4). اخترنا هذا الجزء لالمؤتلف التعبير القابلة للذوبان في E. القولونية وتنقية لاحقة وني NTA. لرصد وmultimerization لمقارنة الغزو في الخلية مع خلية البروتين الغازية مثل وصف α-synuclein، وصفت ونحن DISC1 (598-785) مع صبغة الفلورسنت DyLight594، ومقارنة لهاخلية الغزو مع أن المسمى بنفس القدر من α-synuclein. وزادت بشكل كبير من الخلايا الغازية من جزء DISC1 المؤتلف مقارنة بما كان عليه من طول، الوطنية الكاملة DISC1 aggresomes، من المحتمل بسبب صغر حجمها ونقاوة أعلى من ذلك بكثير. مرة أخرى، يبدو أن نقاء تلعب دورا حاسما في الغزو الخلية. في مثالنا جند aggresomes الغازية القابلة للذوبان البروتين نديد هدف خط الخلية التي أعرب recombinantly في ذوبان، وشكل خلية فرقت أي. التعبير عن بروتين الفلورية (مثل GFP أو RFP) في المتلقي خط الخلية هي ميزة لأنها تسمح للcolocalization من aggresomes الغازية والبروتينات المؤتلف ضمن المستفيدة الحد الخليوي عبر Z-كومة التصوير. aggresomes DISC1 الخلايا الغازية وشظايا multimeric أعرب وتنقيته من E. يمكن أن تكون الإشريكية السمة المميزة لأمراض البروتين المتصلة بتكوين DISC1، DISC1opathies 15. اطلاق النار المتاعب: aggresome العائد المنخفض بعد التدرج تنقية السكروز: التدرج السكروز التي أدخلت في هذا البروتوكول يعمل بشكل جيد مع aggresomes (FL) eGFP/mRFP-DISC1. قد تتكون من البروتينات Aggresomes أخرى تكون ذات أبعاد متغيرة ولذلك يجب أن يكون الأمثل للتركيز السكروز من قبل مستخدمين آخرين. عدم كفاية البروتين المؤتلف تنقية: وينبغي على كل الملوثات البكتيرية في عملية تنقية البروتين المؤتلف يكون المسمى في خطوات لاحقة من البروتوكول. لتجنب التلوث، تشغيل البروتين على SDS-PAGE وتؤكد أن البروتين المؤتلف هو لا يقل عن 95٪ نقية من تلطيخ مع Coomassie أزرق. لضمان أعلى مستويات الجودة والإنتاجية، وبروتوكول يجب أن يكون الأمثل لكل فرد البروتين. انخفاض العلامات EFficiency من البروتينات المؤتلف: فإن أي التلوث التي تحتوي على مجموعات حرة SH-تقليل كفاءة وضع العلامات من البروتين. ولذلك، غسيل الكلى واسعة وني NTA تنقية القائمة على إلزامي.

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> كاشف اسم </td><td> شركة </td><td> كتالوج رقم </td><td> تعليقات </td></tr><tr><td> RPMI 1640 </td><td> إينفيتروجن </td><td> 11875-093 </td><td> متوسطة تعتمد على المضيف خط الخلية. وينبغي تحديد الخلية المتلقية الأمثل خط من قبل المستخدم. </td></tr><tr><td> DMEM/F-12 </td><td> إينفيتروجن </td><td> 11320-033 </td><td> متوسطة تعتمد على المتلقي خط الخلية. وينبغي تحديد الخلية المتلقية الأمثل خط من قبل المستخدم. </td></tr><tr><td> PBS </td><td> إينفيتروجن </td><td> 14190-250 </td><td></td></tr><tr><td> Metafectene </td><td> Biontex </td><td> T020-1.0 </td><td> قد الكواشف ترنسفكأيشن أخرى تعمل كذلك، ولكن لم يتم اختبار مع بروتوكول لدينا. </td></tr><tr><td> ني NTA الاغاروز </td><td> QIAGEN </td><td> 30210 &lt;/ TD&gt; <td> وقد أجريت التجارب مع الاغاروز Ni_NTA من QIAGEN، ينبغي العمل موردين آخرين أيضا. </td></tr><tr><td> الدناز I </td><td> روش </td><td> 04716728001 </td><td> ليست هناك حاجة لريبونوكلياز مجانا الدناز في عملية تنقية aggresomes. </td></tr><tr><td> سكر القصب </td><td> سيغما الدريخ </td><td> S0389 </td><td></td></tr><tr><td> OPTI-MEM </td><td> إينفيتروجن </td><td> 31985-062 </td><td> مصل خالية المتوسطة تعمل كذلك </td></tr><tr><td> البنسلين / الستربتوميسين </td><td> إينفيتروجن </td><td> 15140122 </td><td> ملحق SH-SY5Y والمتوسطة جبهة التحرير الوطني </td></tr><tr><td> غير الضرورية الأحماض الأمينية (NEAA) </td><td> سيغما الدريخ </td><td> M7145 </td><td> ملحق SH-SY5Y المتوسطة </td></tr><tr><td> التريبان الأزرق 0.4٪ </td><td> سيغما الدريخ </td><td> T8154 </td><td> كاشف السامة </td></tr><tr><td> DyLight 594 ماleimide </td><td> الحرارية فيشر العلمية </td><td> 46608 </td><td> تخفيض السيستين صبغ رد الفعل لتشكيل السندات أثير ثيولي مستقرة. كما تتوفر بألوان أخرى. </td></tr><tr><td> إطالة الذهب مع دابي </td><td> إينفيتروجن </td><td> P36935 </td><td> أعطى هذا السائل مرس antifade نتائج متفوقة في أيدينا. </td></tr><tr><td> البروتيني المانع كوكتيل </td><td> روش </td><td> 11873580001 </td><td> حل الجدول 1 في 500 ميكرولتر O 2 H لحل 100X. </td></tr><tr><td> الاصطناعية A-synuclein </td><td> سيجما </td><td> S7820 </td><td> Refold كما هو موضح في النص. </td></tr><tr><td></td><td></td><td></td><td> جدول الكواشف محددة. </td></tr><tr><td> Precellys 24 </td><td> بيرتن تكنولوجيا </td><td> 03119.200.RD000 </td><td> نحن لم نجرب متجانسة الميكانيكية الأخرىغير هذا nizers. طريقة أخرى قد المنظفات تجانس العمل الحر أيضا، ولكن لم يتم اختبارها لهذا البروتوكول. </td></tr><tr><td> 5301 المكثف (speedvac) </td><td> إيبندورف </td><td> 5301 000.210 </td><td> اللازمة إلا إذا البروتين يجب أن تتركز. </td></tr><tr><td> LSM 510 و Apotome2 Axiovision </td><td> زايس </td><td> انظر كتالوج مصنعين </td><td> كل المجاهر تؤوي القدرة على أداء Z-كومة التصوير. هذا هو شرط أساسي لتقييم الصلبة والخطيرة لأحداث الغزو. </td></tr><tr><td> المواد البلاستيكية خلية ثقافة </td><td> نونك </td><td> أطباق 10 سم # 172958، 24 لوحات جيدة # 142475 </td><td> قد استخدام المواد البلاستيكية المختلفة تؤثر على تفاعل البروتينات المؤتلف أو aggresomes والأسطح البلاستيكية. نحن لم تختبر مواد أخرى غير تلك الموصوفة هنا. </td></tr><tr><td></td><td></td><td></td><td> جدول المواد والمعدات الخاصة. </td></tr><tr><td></td><td></td><td></td><td><table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> عدد </td><td> اسم العازلة </td><td> محتوى </td><td> تعليقات </td></tr><tr><td> 1. </td><td> البكتيرية النمو المتوسط </td><td> 16 G / L Bacto تريبتون، 10 Bacto الخميرة ز / لتر استخراج، 5 غرام / لتر كلوريد الصوديوم، 5 ملم أرجينين، حمض الهيدروكلوريك، 5MM MGSO4، 100 ميكروغرام / مل carbencillin، ميكروغرام / 35 مل الكلورامفينيكول </td><td> تنمو البكتيريا إلى OD 600: 0،6-0،8 لحث على التعبير مع IPTG مم 1. </td></tr><tr><td> 2. </td><td> البكتيرية إعادة تعليق العازلة </td><td> 50 ملي تريس، حمض الهيدروكلوريك درجة الحموضة 8.0، 5 ملم EDTA، 2 مم PMSF، 1٪ TX-100، 250 ميكروغرام / مل الليزوزيم، 20 ملم MgCl 2 و 400 مل الدناز I U/50 </td><td> Resupend بيليه البكتيرية من 1 L اوفهrnight الثقافة في 50 مل العازلة إعادة تعليق. </td></tr><tr><td> 3. </td><td> استخراج البروتين المخزن المؤقت </td><td> 50 ملي تريس درجة الحموضة 8.0، 5 ملم إيميدازول، 500 ملي مول كلوريد الصوديوم، 8 M اليوريا و 10 ملي ب-ME </td><td></td></tr><tr><td> 4. </td><td> ني NTA العازلة غسل العمود </td><td> 50 ملي تريس درجة الحموضة 8.0، 5 ملم إيميدازول، 500 ملي مول كلوريد الصوديوم، 8 M اليوريا و 10 ملي ب-ME، 12 مم إيميدازول </td><td> وأضاف تعديل العازلة مع استخراج إيميدازول 12 ملم. </td></tr><tr><td> 5. </td><td> ني NTA العازلة العمود شطف </td><td> 50 ملي تريس، 500 ملي مول كلوريد الصوديوم، 300 مم إيميدازول، 8 M اليوريا، 1 ملم PMSF، 5 ملي EDTA وملي 10 B-ME </td><td> يحتوي المخزن المؤقت شطف ب 10 ملي-ME الذي مدال في وقت لاحق. </td></tr><tr><td> 6. </td><td> PBS </td><td> 8 ز / لتر كلوريد الصوديوم، 0.2 غرام / لتر بوكل، 1.44 غ / ل نا 2 HPO 4، 0،24 غرام / لتر KH 2 PO 4، التكيف مع درجة الحموضة 7.4 </td><td></td></tr><tr><td>7. </td><td> وضع العلامات الفاصلة </td><td> PBS تحتوي على 5 ملي TCEP </td><td></td></tr><tr><td colspan="4"> الجدول من وصفات. </td></tr></tbody></table></td></tr></tbody></table>

generation, purification, and characterization of cell-invasive disc1 protein species

وينظر تجميع البروتين باعتباره السمة المميزة العامة المزمن، وظروف الدماغ التنكسية مثل، على سبيل المثال، في أمراض الاعصاب مرض الزهايمر (Aβ، تاو)، ومرض باركنسون (α-synuclein)، مرض هنتنغتون (polyglutamine، huntingtin)، وغيرها. ويعتقد تجميع البروتين لتحدث نتيجة لاضطراب proteostasis، أي عدم التوازن بين الناشئة وتدهور البروتينات تتجمع. من المذكرة، تم العثور على البروتينات نفس تجميعها في أشكال متفرقة من هذه الأمراض التي هي متحولة في المتغيرات النادرة من أشكال العائلية. الفصام هو حالة مزمنة الدماغ التقدمية التي في كثير من الحالات يسير جنبا إلى جنب مع العجز المعرفي دائمة لا رجعة فيها. في نهج مرشح الجينات، ونحن التحقيق ما إذا كان يمكن العثور على تعطل في والفصام 1 (DISC1)، استنساخ الجين في أسرة الاسكتلندي مع الربط للأمراض العقلية المزمنة 1 و 2، وغير قابلة للذوبان المجاميع في المخن من حالات متفرقة من الفصام 3. باستخدام CC SMRI، حددنا في ما يقرب من 20٪ من الحالات ولكن ليس مع CMD الضوابط العادية أو المرضى الذين يعانون من أمراض الاعصاب تفاعلية مناعية DISC1 sarkosyl غير قابلة للذوبان بعد تجزئة البيوكيميائية. كشفت دراسات لاحقة في المختبر أن تأثر الميل تجميع DISC1 من تعدد الأشكال من الأمراض المرتبطة بها S704C 4، والتي ولدت DISC1 aggresomes في المختبر كانت الخلية الغازية 5، على غرار ما كان قد تعرض لAβ 6، تاو 7-9، α synuclein-10، polyglutamine 11، أو المجاميع SOD1 12. دفعت هذه النتائج لنا أن أقترح أن ما لا يقل عن مجموعة فرعية من الحالات مع CMD، مع تلك DISC1 المجمعة قد تكون اضطرابات البروتين بتكوين. نحن هنا وصف الطريقة التي تولد DISC1 aggresomes في خلايا الثدييات، تنقية لهم على التدرج السكروز واستخدامها لخلية الغزو ستوديوفاق. وبالمثل، نحن تصف كيفية إنشاء multimeric حصريا محطة C-DISC1 جزء، والتسمية وتطهيره للدراسات الغزو الخلية. باستخدام multimers المؤتلف من DISC1 نحقق مماثلة الغزو خلية أما جزء α-synuclein الاصطناعية المسمى بالمثل. نعرض أيضا أن يتم أخذ هذه القطعة حتى عندما تم حقنها في الجسم الحي stereotactically في الدماغ من الحيوانات المتلقية.

Watch this Scientific Journal Video about Generation, Purification, and Characterization of Cell-invasive DISC1 Protein Species at JoVE.com

Generation, Purification, and Characterization of Cell-invasive DISC1 Protein Species

الجيل، وتنقية الخلايا غزو، السيتوبلازمية داخل الخلايا كامل طول البروتين aggresomes DISC1 من مزارع الخلايا لو، multimeric المسمى المؤتلف جزء من البروتين في DISC1<em&gt; E. القولونية</em&gt; موصوفة. ويرد الغزو الخلية لخلايا المتلقي في خلية ثقافة والخلايا العصبية لل<em&gt; في الجسم الحي</em&gt; بعد التلقيح الدماغ stereotactical.

جيل وتنقية، وتوصيف الأنواع الغازية خلية البروتين DISC1

Protein aggregation is seen as a general hallmark of chronic, degenerative brain conditions like, for example, in the neurodegenerative diseases ...

generation-purification-characterization-cell-invasive-disc1-protein

Research

JoVE Journal

Biology

13.6K Views.  Medical School Düsseldorf, Germany. الجيل، وتنقية الخلايا غزو، السيتوبلازمية داخل الخلايا كامل طول البروتين aggresomes DISC1 من مزارع الخلايا لو، multimeric المسمى المؤتلف جزء من البروتين في DISC1 E. القولونية موصوفة. ويرد الغزو الخلية لخلايا المتلقي في خلية ثقافة والخلايا العصبية لل في الجسم الحي

Video: Generation, Purification, and Characterization of Cell-invasive DISC1 Protein Species

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staning of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compunds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

A short protocol for protein staining with Coomassie Brilliant Blue (CBB) G-250 in polyacrylamide gels is described without using organic solvents or acetic acid as in the classical staining procedures with CBB.

تلطيخ من البروتينات في الهلام مع Coomassie G - 250 دون عضوي حمض الخليك والمذيبات

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

Purification of the M. magneticum Strain AMB-1 Magnetosome Associated Protein MamA&Delta;41

Magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. This behavior is believed to aid their search for suitable environments (1). This capability is conferred by the magnetosome, a subcellular organelle that consists of a linear-chain assembly of lipid vesicles each able to biomineralize and enclose a ~50-nm crystal of magnetite or greigite. A principle component of the magnetosome that was shown to be required for the formation of functional vesicles is MamA. MamA is a highly abundant magnetosome-associated protein which is one of the most characterized magnetosome-associated proteins in vivo (2-6). This article focuses on the purification of MamA, which despite being studied in vivo, no clear functional or structural details have been identified for it. Bioinformatics analysis suggested that MamA is a tetra-tricopeptide repeat (TPR) containing protein. TPR is a structural motif found as such or forming part of a bigger fold in a wide range of proteins, it serves as a template for protein-protein interactions and mediates multi-protein complexes (7). TPRs are involved in many crucial tasks in eukaryotic cell organelle processes and many bacterial pathways (8-14). In order to understand MamA, a unique TPR containing protein, highly purified protein is required as a first step. In this article, we present the purification protocol for a stable MamA deletion mutant (MamA&Delta;41) from M. magneticum AMB-1.

Purification of the &lt;em&gt;M. magneticum&lt;/em&gt; Strain AMB-1 Magnetosome Associated Protein MamA&amp;Delta;41

MamA is a unique Magnetosome associated protein which was shown to be involved in magnetosome activation. Here we present the purification protocol of MamA deletion mutant (MamA&Delta;41) from M. magneticum AMB-1.

تنقية م. magneticum سلالة AMB - 1 بروتين المرتبطين Magnetosome MamAΔ41

Magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. This behavior is ...

A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals

Noninvasive genetic sampling approaches are becoming increasingly important to study wildlife populations. A number of studies have reported using noninvasive sampling techniques to investigate population genetics and demography of wild populations1. This approach has proven to be especially useful when dealing with rare or elusive species2. While a number of these methods have been developed to sample hair, feces and other biological material from carnivores and medium-sized mammals, they have largely remained untested in elusive small mammals. In this video, we present a novel, inexpensive and noninvasive hair snare targeted at an elusive small mammal, the American pika (Ochotona princeps). We describe the general set-up of the hair snare, which consists of strips of packing tape arranged in a web-like fashion and placed along travelling routes in the pikas&#x2019; habitat. We illustrate the efficiency of the snare at collecting a large quantity of hair that can then be collected and brought back to the lab. We then demonstrate the use of the DNA IQ system (Promega) to isolate DNA and showcase the utility of this method to amplify commonly used molecular markers including nuclear microsatellites, amplified fragment length polymorphisms (AFLPs), mitochondrial sequences (800bp) as well as a molecular sexing marker. Overall, we demonstrate the utility of this novel noninvasive hair snare as a sampling technique for wildlife population biologists. We anticipate that this approach will be applicable to a variety of small mammals, opening up areas of investigation within natural populations, while minimizing impact to study organisms.

We present a noninvasive sampling approach to efficiently collect hair samples from elusive small mammals, as shown for the American pika. We demonstrate the utility of this method by extracting DNA from sampled hair and amplifying several types of molecular markers commonly used in studies of wildlife ecology and conservation.

عينات الشعر نونينفاسيفي تقنيات الحمض النووي للحصول على ارتفاع الجودة من الثدييات الصغيرة المراوغ

Noninvasive genetic sampling approaches are becoming increasingly important to study wildlife populations. A number of studies have reported using ...

Purification of Hsp104, a Protein Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key selective advantages. First, renaturation of disordered aggregates by Hsp104 empowers yeast survival after various protein-misfolding stresses, including heat shock3,5,11,12. Second, remodeling of cross-beta amyloid fibrils by Hsp104 enables yeast to exploit myriad prions (infectious amyloids) as a reservoir of beneficial and heritable phenotypic variation13-22. Remarkably, Hsp104 directly remodels preamyloid oligomers and amyloid fibrils, including those comprised of the yeast prion proteins Sup35 and Ure223-30. This amyloid-remodeling functionality is a specialized facet of yeast Hsp104. The E. coli orthologue, ClpB, fails to remodel preamyloid oligomers or amyloid fibrils26,31,32.
Hsp104 orthologues are found in all kingdoms of life except, perplexingly, animals. Indeed, whether animal cells possess any enzymatic system that couples protein disaggregation to renaturation (rather than degradation) remains unknown33-35. Thus, we and others have proposed that Hsp104 might be developed as a therapeutic agent for various neurodegenerative diseases connected with the misfolding of specific proteins into toxic preamyloid oligomers and amyloid fibrils4,7,23,36-38. There are no treatments that directly target the aggregated species associated with these diseases. Yet, Hsp104 dissolves toxic oligomers and amyloid fibrils composed of alpha-synuclein, which are connected with Parkinson's Disease23 as well as amyloid forms of PrP39. Importantly, Hsp104 reduces protein aggregation and ameliorates neurodegeneration in rodent models of Parkinson's Disease23 and Huntington's disease38. Ideally, to optimize therapy and minimize side effects, Hsp104 would be engineered and potentiated to selectively remodel specific aggregates central to the disease in question4,7. However, the limited structural and mechanistic understanding of how Hsp104 disaggregates such a diverse repertoire of aggregated structures and unrelated proteins frustrates these endeavors30,40-42.
To understand the structure and mechanism of Hsp104, it is essential to study the pure protein and reconstitute its disaggregase activity with minimal components. Hsp104 is a 102kDa protein with a pI of ~5.3, which hexamerizes in the presence of ADP or ATP, or at high protein concentrations in the absence of nucleotide43-46. Here, we describe an optimized protocol for the purification of highly active, stable Hsp104 from E. coli. The use of E. coli allows simplified large-scale production and our method can be performed quickly and reliably for numerous Hsp104 variants. Our protocol increases Hsp104 purity and simplifies His6-tag removal compared to a previous purification method from E. coli47. Moreover, our protocol is more facile and convenient than two more recent protocols26,48.

Here, we describe a protocol for the purification of highly active Hsp104, a hexameric AAA+ protein from yeast, which couples ATP hydrolysis to protein disaggregation. This scheme exploits a His6-tagged construct for affinity purification from E. coli followed by anion-exchange chromatography, His6-tag removal with TEV protease, and size-exclusion chromatography.

تنقية Hsp104 ، وهو بروتين Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key ...

Identification of Protein Interacting Partners Using Tandem Affinity Purification

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein partners. There are many approaches that allow the identification of interacting partners, including the yeast two hybrid system, as well as pull down assays using recombinant proteins and immunoprecipitation of endogenous proteins followed by mass spectrometry identification1. Recent studies have highlighted the utility of double-affinity tag mediated purification, coupled with two specific elution steps in the identification of interacting proteins. This approach, termed Tandem Affinity Purification (TAP), was initially used in yeast2,3 but more recently has been adapted to use in mammalian cells4-8.
As proof-of-concept we have established a tandem affinity purification (TAP) method using the well-characterized eukaryotic translation initiation factor eIF4E9,10.The cellular translation factor eIF4E is a critical component of the cellular eIF4F complex involved in cap-dependent translation initiation10. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence8. To forgo the need for the generation of clonal cell lines, we developed a rapid system that relies on the expression of the TAP-tagged bait protein from an episomally maintained plasmid based on pMEP4 (Invitrogen). Expression of tagged murine eIF4E from this plasmid was controlled using the cadmium chloride inducible metallothionein promoter.
Lysis of the expressing cells and subsequent affinity purification via binding to rabbit IgG agarose, TEV protease cleavage, binding to streptavidin linked agarose and subsequent biotin elution identified numerous proteins apparently specific to the eIF4E pull-down (when compared to control cell lines expressing the TAP tag alone). The identities of the proteins were obtained by excision of the bands from 1D SDS-PAGE and subsequent tandem mass spectrometry. The identified components included the known eIF4E binding proteins eIF4G and 4EBP-1. In addition, other components of the eIF4F complex, of which eIF4E is a component were identified, namely eIF4A and Poly-A binding protein. The ability to identify not only known direct binding partners as well as secondary interacting proteins, further highlights the utility of this approach in the characterization of proteins of unknown function.

Tandem affinity purification is a robust approach for the identification of protein binding partners. As proof of concept, this methodology was applied to the well-characterized translation initiation factor eIF4E to co-precipitate the host cell factors involved in translation initiation. This method is easily adapted to any cellular or viral protein.

تحديد الشركاء البروتين عن طريق التفاعل جنبا الى جنب الانجذاب تنقية

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein ...

Identification and Characterization of Protein Glycosylation using Specific Endo- and Exoglycosidases

Glycosylation, the addition of covalently linked sugars, is a major post-translational modification of proteins that can significantly affect processes such as cell adhesion, molecular trafficking, clearance, and signal transduction1-4. In eukaryotes, the most common glycosylation modifications in the secretory pathway are additions at consensus asparagine residues (N-linked); or at serine or threonine residues (O-linked) (Figure 1). Initiation of N-glycan synthesis is highly conserved in eukaryotes, while the end products can vary greatly among different species, tissues, or proteins. Some glycans remain unmodified ("high mannose N-glycans") or are further processed in the Golgi ("complex N-glycans"). Greater diversity is found for O-glycans, which start with a common N-Acetylgalactosamine (GalNAc) residue in animal cells but differ in lower organisms1.
The detailed analysis of the glycosylation of proteins is a field unto itself and requires extensive resources and expertise to execute properly. However a variety of available enzymes that remove sugars (glycosidases) makes possible to have a general idea of the glycosylation status of a protein in a standard laboratory setting. Here we illustrate the use of glycosidases for the analysis of a model glycoprotein: recombinant human chorionic gonadotropin beta (hCG&beta;), which carries two N-glycans and four O-glycans 5. The technique requires only simple instrumentation and typical consumables, and it can be readily adapted to the analysis of multiple glycoprotein samples.
Several enzymes can be used in parallel to study a glycoprotein. PNGase F is able to remove almost all types of N-linked glycans6,7. For O-glycans, there is no available enzyme that can cleave an intact oligosaccharide from the protein backbone. Instead, O-glycans are trimmed by exoglycosidases to a short core, which is then easily removed by O-Glycosidase. The Protein Deglycosylation Mix contains PNGase F, O-Glycosidase, Neuraminidase (sialidase), &beta;1-4 Galactosidase, and &beta;-N-Acetylglucosaminidase. It is used to simultaneously remove N-glycans and some O-glycans8 . Finally, the Deglycosylation Mix was supplemented with a mixture of other exoglycosidases (&alpha;-N-Acetylgalactosaminidase, &alpha;1-2 Fucosidase, &alpha;1-3,6 Galactosidase, and &beta;1-3 Galactosidase ), which help remove otherwise resistant monosaccharides that could be present in certain O-glycans.
SDS-PAGE/Coomasie blue is used to visualize differences in protein migration before and after glycosidase treatment. In addition, a sugar-specific staining method, ProQ Emerald-300, shows diminished signal as glycans are successively removed. This protocol is designed for the analysis of small amounts of glycoprotein (0.5 to 2 &mu;g), although enzymatic deglycosylation can be scaled up to accommodate larger quantities of protein as needed.

Using specific glycosidases to remove sugars from glycoproteins followed by SDS-PAGE is a valuable method to detect glycan modifications on protein samples and is a good choice for initial glycobiology studies. Changes following deglycosylation can be detected as shifts in gel mobility or by staining with glycan sensitive reagents.

تحديد وتوصيف ارتباط بالغليكوزيل باستخدام بروتين معين إندو وexoglycosidases

Glycosylation, the addition of covalently linked sugars, is a major post-translational modification of proteins that can significantly affect processes ...

Expression and Purification of the Cystic Fibrosis Transmembrane Conductance Regulator Protein in Saccharomyces cerevisiae

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel, that when mutated, can give rise to cystic fibrosis in humans.There is therefore considerable interest in this protein, but efforts to study its structure and activity have been hampered by the difficulty of expressing and purifying sufficient amounts of the protein1-3. Like many 'difficult' eukaryotic membrane proteins, expression in a fast-growing organism is desirable, but challenging, and in the yeast S. cerevisiae, so far low amounts were obtained and rapid degradation of the recombinant protein was observed 4-9. Proteins involved in the processing of recombinant CFTR in yeast have been described6-9 .In this report we describe a methodology for expression of CFTR in yeast and its purification in significant amounts. The protocol describes how the earlier proteolysis problems can be overcome and how expression levels of CFTR can be greatly improved by modifying the cell growth conditions and by controlling the induction conditions, in particular the time period prior to cell harvesting. The reagants associated with this protocol (murine CFTR-expressing yeast cells or yeast plasmids) will be distributed via the US Cystic Fibrosis Foundation, which has sponsored the research. An article describing the design and synthesis of the CFTR construct employed in this report will be published separately (Urbatsch, I.; Thibodeau, P. et al., unpublished). In this article we will explain our method beginning with the transformation of the yeast cells with the CFTR construct - containing yeast plasmid (Fig. 1). The construct has a green fluorescent protein (GFP) sequence fused to CFTR at its C-terminus and follows the system developed by Drew et al. (2008)10. The GFP allows the expression and purification of CFTR to be followed relatively easily. The JoVE visualized protocol finishes after the preparation of microsomes from the yeast cells, although we include some suggestions for purification of the protein from the microsomes. Readers may wish to add their own modifications to the microsome purification procedure, dependent on the final experiments to be carried out with the protein and the local equipment available to them. The yeast-expressed CFTR protein can be partially purified using metal ion affinity chromatography, using an intrinsic polyhistidine purification tag. Subsequent size-exclusion chromatography yields a protein that appears to be &gt;90% pure, as judged by SDS-PAGE and Coomassie-staining of the gel.

Expression and Purification of the Cystic Fibrosis Transmembrane Conductance Regulator Protein in Saccharomyces cerevisiae

Attempts to express the cystic fibrosis transmembrane conductance regulator (CFTR) in Saccharomyces cerevisiae have, until now, yielded relatively low amounts of protein. This protocol and the associated reagents distributed via the Cystic Fibrosis Foundation should allow the preparation of milligram amounts of this 'difficult' eukaryotic membrane protein.

التعبير وتنقية عبر الغشاء التليف الكيسي بروتين منظم المواصلة في خميرة الخباز

The  cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride  channel, that when mutated, can give rise to cystic fibrosis in  ...

Protein Purification-free Method of Binding Affinity Determination by Microscale Thermophoresis

Quantitative characterization of protein interactions is essential in practically any field of life sciences, particularly drug discovery. Most of currently available methods of KD determination require access to purified protein of interest, generation of which can be time-consuming and expensive. We have developed a protocol that allows for determination of binding affinity by microscale thermophoresis (MST) without purification of the target protein from cell lysates. The method involves overexpression of the GFP-fused protein and cell lysis in non-denaturing conditions. Application of the method to STAT3-GFP transiently expressed in HEK293 cells allowed to determine for the first time the affinity of the well-studied transcription factor to oligonucleotides with different sequences. The protocol is straightforward and can have a variety of application for studying interactions of proteins with small molecules, peptides, DNA, RNA, and proteins.

Microscale thermophoresis (MST) can be widely used for determination of binding affinity without purification of the target protein from cell lysates. The protocol involves overexpression of the GFP-fused protein, cell lysis in non-denaturing conditions, and detection of MST signal in the presence of varying concentrations of the ligand.

البروتين طريقة خالية من تنقية تجليد تحديد الانجذاب من قبل Thermophoresis الميكروسكيل

Quantitative characterization of protein  interactions is essential in practically any field of life sciences,  particularly drug discovery. Most of ...

Detecting, Visualizing and Quantitating the Generation of Reactive Oxygen Species in an Amoeba Model System

Reactive oxygen species (ROS) comprise a range of reactive and short-lived, oxygen-containing molecules, which are dynamically interconverted or eliminated either catalytically or spontaneously. Due to the short life spans of most ROS and the diversity of their sources and subcellular localizations, a complete picture can be obtained only by careful measurements using a combination of protocols. Here, we present a set of three different protocols using OxyBurst Green (OBG)-coated beads, or dihydroethidium (DHE) and Amplex UltraRed (AUR), to monitor qualitatively and quantitatively various ROS in professional phagocytes such as Dictyostelium. We optimised the beads coating procedures and used OBG-coated beads and live microscopy to dynamically visualize intraphagosomal ROS generation at the single cell level. We identified lipopolysaccharide (LPS) from E. coli as a potent stimulator for ROS generation in Dictyostelium. In addition, we developed real time, medium-throughput assays using DHE and AUR to quantitatively measure intracellular superoxide and extracellular H2O2 production, respectively.

We adapted a set of protocols for the measurement of reactive oxygen species (ROS) that can be applied in various amoeba and mammalian cellular models for qualitative and quantitative studies.

كشف، تصور وQuantitating الجيل من أنواع الاكسجين التفاعلية في النظام النموذجي الاميبا

Reactive oxygen species (ROS) comprise a range of reactive and short-lived, oxygen-containing molecules, which are dynamically interconverted or ...

Identifying Protein-protein Interaction in Drosophila Adult Heads by Tandem Affinity Purification (TAP)

Genetic screens conducted using Drosophila melanogaster (fruit fly) have made numerous milestone discoveries in the advance of biological sciences. However, the use of biochemical screens aimed at extending the knowledge gained from genetic analysis was explored only recently. Here we describe a method to purify the protein complex that associates with any protein of interest from adult fly heads. This method takes advantage of the Drosophila GAL4/UAS system to express a bait protein fused with a Tandem Affinity Purification (TAP) tag in fly neurons in vivo, and then implements two rounds of purification using a TAP procedure similar to the one originally established in yeast1 to purify the interacting protein complex. At the end of this procedure, a mixture of multiple protein complexes is obtained whose molecular identities can be determined by mass spectrometry. Validation of the candidate proteins will benefit from the resource and ease of performing loss-of-function studies in flies. Similar approaches can be applied to other fly tissues. We believe that the combination of genetic manipulations and this proteomic approach in the fly model system holds tremendous potential for tackling fundamental problems in the field of neurobiology and beyond.

Identifying Protein-protein Interaction in Drosophila Adult Heads by Tandem Affinity Purification TAP

Drosophila is famous for its powerful genetic manipulation, but not for its suitability of in-depth biochemical analysis. Here we present a TAP-based procedure to identify interacting partners of any protein of interest from the fly brain. This procedure can potentially lead to new avenues of research.

تحديد البروتين البروتين التفاعل في<em&gt; ذبابة الفاكهة</em&gt; رؤساء الكبار حسب جنبا الى جنب الانجذاب تنقية (وات)

Genetic screens conducted using Drosophila melanogaster (fruit fly) have made numerous milestone discoveries in the advance of biological sciences. ...