Name: purification of hsp104, a protein disaggregase
Uploaded: 2011-09-30T13:00:00
Description: Watch this Scientific Journal Video about Purification of Hsp104, a Protein Disaggregase at JoVE.com

Ce travail a été soutenu par une subvention du NIH (5T32GM008275-22) et une bourse de l&#39;American Heart Association prédoctoral (à EAS); une bourse de l&#39;interface chimie-biologie du NIH (2T32GM071339-06A1) (à MED) et des subventions de la NIH (1DP2OD002177-01 et NS067354-0110), Le Ellison Medical Foundation et la Fondation Bill et Melinda Gates Foundation (JS).

1. Expression de Hsp104 <ol><li> Le plasmide utilisé pour la purification dans E. coli, pPROEX-HTB-Hsp104, contient les Hsp104 ouvert cadre de lecture sous le contrôle du promoteur inductible TRC 26. Le plasmide produit Hsp104 avec un N-terminale Sa 6-tag qui peut être enlevée par clivage de la protéase TEV. Transformez pPROEX-HTB-Hsp104 en codon optimisé E. coli BL21-CodonPlus-RIL cellules (Stratagene, Agilent Technologies) en utilisant une procédure de transfor...

Chronologie: Pour Hsp104 activité maximale, nous recommandons que le schéma de purification entière soit achevée aussi rapidement que possible. Cependant, le nombre d&#39;étapes de purification rend un horaire exigeant qui ne peuvent pas toujours être pratique. Si les étapes de purification sont effectués aussi rapidement que possible, le temps de la fin de l&#39;expression du jour au lendemain grâce à l&#39;2-4 heures d&#39;incubation à 30 ° C avec TEV protéase est d&#39;environ 9-11 heures. Un lieu...

<table border="1"><tbody><tr><th> Nom du réactif </th><th> Société </th><th> Numéro de catalogue </th></tr><tr><td> BL21-CodonPlus-RIL cellules compétentes </td><td> Stratagene, Agilent Technologies </td><td> 230255 </td></tr><tr><td> 2xYT bouillon </td><td> USB </td><td> 75864 </td></tr><tr><td> Complète, mini, de l&#39;EDTA-libres comprimés inhibiteur de protéase </td><td> Roche </td><td> 1836170 </td></tr><tr><td> Pepstatine A </td><td> Sigma </td><td> P4265 </td></tr><tr><td> Ni-Sépharose 6 Fast Flow </td><td> GE Healthcare </td><td> 17-5318-02 </td></tr><tr><td> Amicon Ultra-15 centrifuges unités de filtration (MWCO 30000) </td><td> Millipore </td><td> UFC903008 </td></tr><tr><td> Resource Q - colonne de 6ml </td><td> GE Healthcare </td><td> 17-1179-01 </td></tr><tr><td> proTEV protéase </td><td> Promega </td><td> V6052 </td></tr><tr><td> AcTEV protéase </td><td> Invitrogen </td><td> 12575015 </td></tr><tr><td> Superose 6 10/300 GL </td><td> GE Healthcare </td><td> 17-5172-01 </td></tr><tr><td> HSP40 </td><td> Assay Designs </td><td> PSP-400 </td></tr><tr><td> Hsp72 </td><td> Assay Designs </td><td> ADI-NSP-555 </td></tr></tbody></table>

purification of hsp104, a protein disaggregase

Hsp104 est un hexamère AAA + 1 à partir de protéines de la levure, qui couple l&#39;hydrolyse d&#39;ATP à la protéine de désagrégation 2-10 (Fig. 1). Cette activité confère deux grands avantages sélectifs. Tout d&#39;abord, la renaturation des agrégats désordonnés par Hsp104 permet la survie de la levure après diverses protéines-repliement souligne, notamment 3,5,11,12 choc thermique. Deuxièmement, le remodelage des fibrilles amyloïdes bêta par la Croix-Hsp104 permet d&#39;exploiter la levure prions myriades (amyloïdes infectieux) comme un réservoir de bénéfique et héritable variation phénotypique 13-22. Remarquablement, Hsp104 remodèle directement oligomères preamyloid et fibrilles amyloïdes, y compris ceux comprenant des protéines prion de levure et de SUP35 URE2 23-30. Cette fonctionnalité amyloïde remodelage est une facette spécialisée de la levure Hsp104. Le E. orthologue coli, CLPB, ne parvient pas à transformer ou oligomères preamyloid fibrilles amyloïdes 26,31,32. Orthologues Hsp104 se trouvent dans tous les règnes de la vie, sauf, perplexingly, les animaux. En effet, si les cellules animales possèdent aucun système enzymatique que la désagrégation de protéines aux couples de renaturation (plutôt que de la dégradation) demeure inconnue 33-35. Ainsi, nous et d&#39;autres ont proposé que Hsp104 pourrait être développé comme un agent thérapeutique pour diverses maladies neurodégénératives liées au mauvais repliement de protéines spécifiques dans les oligomères preamyloid toxiques et fibrilles amyloïdes 4,7,23,36-38. Il n&#39;y a pas de traitements qui ciblent directement les espèces agrégées associées à ces maladies. Pourtant, Hsp104 dissout oligomères toxiques et fibrilles amyloïdes composé d&#39;alpha-synucléine, qui sont liés à la maladie de Parkinson 23 ainsi que les formes de PrP amyloïde 39. Surtout, Hsp104 réduit l&#39;agrégation des protéines et améliore la neurodégénérescence dans des modèles rongeurs de la maladie de Parkinson et la maladie de Huntington 23 38. Idéalement, pour optimiser le traitement et de minimiser les effets secondaires, Hsp104 serait conçu et potentialisé de façon sélective remodeler agrégats spécifiques au centre de la maladie en question 4,7. Cependant, la compréhension limitée structurelles et mécanistiques sur la manière dont Hsp104 désagrège un tel répertoire varié de structures agrégées et les protéines non liées frustre ces efforts 30,40-42. Pour comprendre la structure et le mécanisme de Hsp104, il est essentiel d&#39;étudier la protéine pure et reconstituer son activité disaggregase avec des composants minimes. Hsp104 est une protéine 102kDa avec un pI de 5,3 ~, qui hexamerizes, en présence de l&#39;ADP ou l&#39;ATP, ou à des concentrations élevées de protéines en l&#39;absence de 43-46 nucléotides. Ici, nous décrivons un protocole optimisé pour la purification de très actif, stable Hsp104 de E. coli. L&#39;utilisation de E. coli permet simplifiée production à grande échelle et à notre méthode peut être effectuée rapidement et de manière fiable pour de nombreuses variantes Hsp104. Notre protocole augmente Hsp104 pureté et simplifie son 6-tag retrait par rapport à un procédé de purification préalable de E. coli 47. Par ailleurs, notre protocole est plus facile et pratique de deux protocoles les plus récents 26,48.

Watch this Scientific Journal Video about Purification of Hsp104, a Protein Disaggregase at JoVE.com

Purification of Hsp104, a Protein Disaggregase

Ici, nous décrivons un protocole pour la purification de la très active Hsp104, un AAA + hexamérique protéines de la levure, qui couple l&#39;hydrolyse d&#39;ATP à la désagrégation des protéines. Ce schéma exploite une construction His6-marqués pour la purification d&#39;affinité à partir<em&gt; E. coli</em&gt; Suivie par chromatographie échangeuse d&#39;anions, His6-tag retrait avec la protéase TEV, et chromatographie d&#39;exclusion stérique.

Purification de Hsp104, une protéine Disaggregase

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

purification-of-hsp104-a-protein-disaggregase

Research

JoVE Journal

Biology

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.

Coloration des protéines dans les gels de Coomassie G-250, sans solvant et l&#39;acide acétique organique

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

Recherche

Biologie

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.

Purification de la M. magneticum Strain AMB-1 Protein magnétosome Associated MamAΔ41

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

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein

Multidrug resistance (MDR), the ability of a cancer cell or pathogen to be resistant to a wide range of structurally and functionally unrelated anti-cancer drugs or antibiotics, is a current serious problem in public health. This multidrug resistance is largely due to energy-dependent drug efflux pumps. The pumps expel anti-cancer drugs or antibiotics into the external medium, lowering their intracellular concentration below a toxic threshold. We are studying multidrug resistance in Pseudomonas aeruginosa, an opportunistic bacterial pathogen that causes infections in patients with many types of injuries or illness, for example, burns or cystic fibrosis, and also in immuno-compromised cancer, dialysis, and transplantation patients. The major MDR efflux pumps in P. aeruginosa are tripartite complexes comprised of an inner membrane proton-drug antiporter (RND), an outer membrane channel (OMF), and a periplasmic linker protein (MFP) 1-8. The RND and OMF proteins are transmembrane proteins. Transmembrane proteins make up more than 30% of all proteins and are 65% of current drug targets. The hydrophobic transmembrane domains make the proteins insoluble in aqueous buffer. Before a transmembrane protein can be purified, it is necessary to find buffer conditions containing a mild detergent that enable the protein to be solubilized as a protein detergent complex (PDC) 9-11. In this example, we use an RND protein, the P. aeruginosa MexB transmembrane transporter, to demonstrate how to express a recombinant form of a transmembrane protein, solubilize it using detergents, and then purify the protein detergent complexes. This general method can be applied to the expression, purification, and solubilization of many other recombinantly expressed membrane proteins. The protein detergent complexes can later be used for biochemical or biophysical characterization including X-ray crystal structure determination or crosslinking studies.

In this protocol we demonstrate the expression, solubilization, and purification of a recombinantly expressed membrane protein, MexB, as a soluble protein detergent complex. MexB is a multidrug resistance membrane transporter from the opportunistic bacterial pathogen Pseudomonas aeruginosa.

Expression, Solubilisation détergent, et purification d&#39;un transporteur membranaire, la protéine MexB multirésistance

Multidrug resistance (MDR), the ability of a cancer cell or pathogen to be resistant to a wide range of structurally and functionally unrelated ...

Chromatographic Purification of Highly Active Yeast Ribosomes

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers. Particularly troublesome is the fact that lysis of cells releases a large number of proteases and nucleases which can degrade ribosomes. Thus, it is important to separate ribosomes from these enzymes as quickly as possible. Unfortunately, conventional differential ultracentrifugation methods leaves ribosomes exposed to these enzymes for unacceptably long periods of time, impacting their structural integrity and functionality. To address this problem, we utilize a chromatographic method using a cysteine charged Sulfolink resin. This simple and rapid application significantly reduces co-purifying proteolytic and nucleolytic activities, producing high yields of intact, highly biochemically active yeast ribosomes. We suggest that this method should also be applicable to mammalian ribosomes. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

Contamination of preparations of eukaryotic ribosomes purified by traditional methods by co-purifying nucleases and proteases negatively impacts on downstream biochemical and structural analyses. A rapid and simple chromatographic purification method is used to solve this problem using yeast ribosomes as a model system.

Purification chromatographique des ribosomes de levure hautement active

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers.  ...

Orthogonal Protein Purification Facilitated by a Small Bispecific Affinity Tag

Due to the high costs associated with purification of recombinant proteins the protocols need to be rationalized. For high-throughput efforts there is a demand for general methods that do not require target protein specific optimization1 . To achieve this, purification tags that genetically can be fused to the gene of interest are commonly used2 . The most widely used affinity handle is the hexa-histidine tag, which is suitable for purification under both native and denaturing conditions3 . The metabolic burden for producing the tag is low, but it does not provide as high specificity as competing affinity chromatography based strategies1,2.
Here, a bispecific purification tag with two different binding sites on a 46 amino acid, small protein domain has been developed. The albumin-binding domain is derived from Streptococcal protein G and has a strong inherent affinity to human serum albumin (HSA). Eleven surface-exposed amino acids, not involved in albumin-binding4 , were genetically randomized to produce a combinatorial library. The protein library with the novel randomly arranged binding surface (Figure 1) was expressed on phage particles to facilitate selection of binders by phage display technology. Through several rounds of biopanning against a dimeric Z-domain derived from Staphylococcal protein A5, a small, bispecific molecule with affinity for both HSA and the novel target was identified6 .
The novel protein domain, referred to as ABDz1, was evaluated as a purification tag for a selection of target proteins with different molecular weight, solubility and isoelectric point. Three target proteins were expressed in Escherishia coli with the novel tag fused to their N-termini and thereafter affinity purified. Initial purification on either a column with immobilized HSA or Z-domain resulted in relatively pure products. Two-step affinity purification with the bispecific tag resulted in substantial improvement of protein purity. Chromatographic media with the Z-domain immobilized, for example MabSelect SuRe, are readily available for purification of antibodies and HSA can easily be chemically coupled to media to provide the second matrix.
This method is especially advantageous when there is a high demand on purity of the recovered target protein. The bifunctionality of the tag allows two different chromatographic steps to be used while the metabolic burden on the expression host is limited due to the small size of the tag. It provides a competitive alternative to so called combinatorial tagging where multiple tags are used in combination1,7.

A novel and highly efficient two-step affinity chromatography protocol has been developed and is described in detail. The method is based on a small purification tag with two inherent affinities and is applicable to a wide range of target proteins with different properties.

Protein Purification Orthogonal Animé par une étiquette d&#39;affinité bispécifiques petits

Due to the high costs associated with purification of recombinant proteins the protocols need to be rationalized. For high-throughput efforts there is a ...

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.

Identification des partenaires protéine interagissant Utilisation 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 ...

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

Protein aggregation is seen as a general hallmark of chronic, degenerative brain conditions like, for example, in the neurodegenerative diseases Alzheimer's disease (A&beta;, tau), Parkinson's Disease (&alpha;-synuclein), Huntington's disease (polyglutamine, huntingtin), and others. Protein aggregation is thought to occur due to disturbed proteostasis, i.e. the imbalance between the arising and degradation of misfolded proteins. Of note, the same proteins are found aggregated in sporadic forms of these diseases that are mutant in rare variants of familial forms.
Schizophrenia is a chronic progressive brain condition that in many cases goes along with a permanent and irreversible cognitive deficit. In a candidate gene approach, we investigated whether Disrupted-in-schizophrenia 1 (DISC1), a gene cloned in a Scottish family with linkage to chronic mental disease1, 2, could be found as insoluble aggregates in the brain of sporadic cases of schizophrenia3. Using the SMRI CC, we identified in approximately 20 % of cases with CMD but not normal controls or patients with neurodegenerative diseases sarkosyl-insoluble DISC1 immunoreactivity after biochemical fractionation. Subsequent studies in vitro revealed that the aggregation propensity of DISC1 was influenced by disease-associated polymorphism S704C4, and that DISC1 aggresomes generated in vitro were cell-invasive5, similar to what had been shown for A&beta;6, tau7-9, &alpha;-synuclein10, polyglutamine11, or SOD1 aggregates12. These findings prompted us to propose that at least a subset of cases with CMD, those with aggregated DISC1 might be protein conformational disorders.
 Here we describe how we generate DISC1 aggresomes in mammalian cells, purify them on a sucrose gradient and use them for cell-invasiveness studies. Similarly, we describe how we generate an exclusively multimeric C-terminal DISC1 fragment, label and purify it for cell invasiveness studies. Using the recombinant multimers of DISC1 we achieve similar cell invasiveness as for a similarly labeled synthetic &alpha;-synuclein fragment. We also show that this fragment is taken up in vivo when stereotactically injected into the brain of recipient animals.

The generation, purification and cell invasion of intracellular, cytoplasmic full length DISC1 protein aggresomes from cell cultures and of a labeled, multimeric recombinant DISC1 protein fragment in E. coli are described. Cell invasiveness is shown for recipient cells in cell culture and for neurons in vivo after stereotactical brain inoculation.

Production, de conditionnement, et la caractérisation des cellules invasives Espèces protéine DISC1

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

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.

Protein Purification méthode sans la détermination de l&#39;affinité de liaison par thermophorèse Microscale

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

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.

Identifier les interactions protéine-protéine dans<em&gt; Drosophila</em&gt; Têtes de Tandem Affinity Purification adultes (TAP)

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

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

Defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein cause cystic fibrosis (CF), an autosomal recessive disease that currently limits the average life expectancy of sufferers to &#60;40 years of age. The development of novel drug molecules to restore the activity of CFTR is an important goal in the treatment CF, and the isolation of functionally active CFTR is a useful step towards achieving this goal.
We describe two methods for the purification of CFTR from a eukaryotic heterologous expression system, S. cerevisiae. Like prokaryotic systems, S. cerevisiae can be rapidly grown in the lab at low cost, but can also traffic and posttranslationally modify large membrane proteins. The selection of detergents for solubilization and purification is a critical step in the purification of any membrane protein. Having screened for the solubility of CFTR in several detergents, we have chosen two contrasting detergents for use in the purification that allow the final CFTR preparation to be tailored to the subsequently planned experiments.
In this method, we provide comparison of the purification of CFTR in dodecyl-&#946;-D-maltoside (DDM) and 1-tetradecanoyl-sn-glycero-3-phospho-(1&#39;-rac-glycerol) (LPG-14). Protein purified in DDM by this method shows ATPase activity in functional assays. Protein purified in LPG-14 shows high purity and yield, can be employed to study post-translational modifications, and can be used for structural methods such as small-angle X-ray scattering and electron microscopy. However it displays significantly lower ATPase activity.

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

Heterologous expression and purification of the cystic fibrosis transmembrane conductance regulator (CFTR) are significant challenges and limiting factors in the development of drug therapies for cystic fibrosis. This protocol describes two methods for the isolation of milligram quantities of CFTR suitable for functional and structural studies.&#160;