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Ajayi OO, Peters SO, De Donato M, Mujibi FD, Khan WA, Hussain T, Babar ME, Imumorin IG, Thomas BN. Genetic variation in N- and C-terminal regions of bovine DNAJA1 heat shock protein gene in African, Asian and American cattle. J Genomics 2018; 6:1-8. [PMID: 29290829 PMCID: PMC5744232 DOI: 10.7150/jgen.23248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/18/2017] [Indexed: 11/12/2022] Open
Abstract
DNAJA1 or heat shock protein 40 (Hsp40) is associated with heat adaptation in various organisms. We amplified and sequenced a total of 1,142 bp of bovine Hsp40 gene representing the critical N-terminal (NTR) and C-terminal (CTR) regions in representative samples of African, Asian and American cattle breeds. Eleven and 9 different haplotypes were observed in the NTR in Asian and African breeds respectively while in American Brangus, only two mutations were observed resulting in two haplotypes. The CTR appears to be highly conserved between cattle and yak. In-silico functional analysis with PANTHER predicted putative deleterious functional impact of c.161 T>A; p. V54Q while alignment of bovine and human NTR-J domains revealed that p.Q19H, p.E20Q and p. E21X mutations occurred in helix 2 and p.V54Q missense mutation occurred in helix 3 respectively. The 124 bp insertion found in the yak DNAJA1 ortholog may have significant functional relevance warranting further investigation. Our results suggest that these genetic differences may be concomitant with population genetic history and possible functional consequences for climate adaptation in bovidae.
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Affiliation(s)
- Oyeyemi O. Ajayi
- Animal Genetics and Genomics Laboratory, International Programs, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
| | - Sunday O. Peters
- Department of Animal Science, Berry College, Mount Berry, GA 30149
- Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602
| | - Marcos De Donato
- Animal Genetics and Genomics Laboratory, International Programs, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
- Departamento Regional de Bioingenierias, Instituto Tecnologico y de Estudios Superiores de Monterrey, Queretaro, Mexico
| | - F. Denis Mujibi
- Usomi Ltd., PO Box 105086-00101, Ushirika Road, Karen, Nairobi, Kenya
| | - Waqas A. Khan
- Animal Genetics and Genomics Laboratory, International Programs, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
- Department of Biotechnology, University of Sargodha, Sargodha, Pakistan
| | - Tanveer Hussain
- Animal Genetics and Genomics Laboratory, International Programs, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
- Department of Molecular Biology, Virtual University of Pakistan, Lahore, Pakistan
| | - Masroor E. Babar
- African Institute for Biosciences Research and Training, Ibadan, Nigeria
| | - Ikhide G. Imumorin
- Animal Genetics and Genomics Laboratory, International Programs, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- African Institute for Biosciences Research and Training, Ibadan, Nigeria
| | - Bolaji N. Thomas
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester NY, 14623
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2
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Parent R, Qu X, Petit MA, Beretta L. The heat shock cognate protein 70 is associated with hepatitis C virus particles and modulates virus infectivity. Hepatology 2009; 49:1798-809. [PMID: 19434724 PMCID: PMC4605602 DOI: 10.1002/hep.22852] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED There is growing evidence that virus particles contain host cell proteins. These proteins may provide viruses with means to evade the immune system or with mechanisms for cell entry and release. A proteomic analysis performed on highly purified hepatitis C virus (HCV) J6/JFH virions identified the heat shock cognate protein 70 (HSC70) as part of the viral particles. These results were further validated via immunogold electron microscopy. The HSC70 interaction HPD motif was found present on the E2 envelope of the J6/JFH strain, as well as in over 50% of genotype 2 clinical HCV isolates. In addition, HSC70 was found associated with viral particles from an HCV genotype 2a-infected patient. Preincubation of HCV particles with anti-HSC70 antibodies decreased viral infectivity. Within infected cells, colocalization of HSC70 with the HCV core and E2 proteins was observed around lipid droplets. Reduction of HSC70 expression using an RNA interference approach decreased the volume of lipid droplets as well as viral release without affecting HCV replication levels. CONCLUSION These results suggest that HSC70 modulates HCV infectivity and lipid droplet-dependent virus release.
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Affiliation(s)
- Romain Parent
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Xiaoyu Qu
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Marie-Anne Petit
- INSERM, U871, 151 Cours Albert Thomas, 69424 Lyon Cedex 03, Université Lyon 1, IFR62 Lyon-Est, 69008 Lyon, France
| | - Laura Beretta
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA,Corresponding author: Laura Beretta, Public Health Sciences Division, Fred Hutchinson Cancer Research Center (M5-A864), Seattle, WA 98109, Phone: 206-667-7080, Fax: 206-667-2537,
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3
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Berjanskii MV, Wishart DS. Application of the random coil index to studying protein flexibility. JOURNAL OF BIOMOLECULAR NMR 2008; 40:31-48. [PMID: 17985196 DOI: 10.1007/s10858-007-9208-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 10/10/2007] [Indexed: 05/19/2023]
Abstract
Protein flexibility lies at the heart of many protein-ligand binding events and enzymatic activities. However, the experimental measurement of protein motions is often difficult, tedious and error-prone. As a result, there is a considerable interest in developing simpler and faster ways of quantifying protein flexibility. Recently, we described a method, called Random Coil Index (RCI), which appears to be able to quantitatively estimate model-free order parameters and flexibility in protein structural ensembles using only backbone chemical shifts. Because of its potential utility, we have undertaken a more detailed investigation of the RCI method in an attempt to ascertain its underlying principles, its general utility, its sensitivity to chemical shift errors, its sensitivity to data completeness, its applicability to other proteins, and its general strengths and weaknesses. Overall, we find that the RCI method is very robust and that it represents a useful addition to traditional methods of studying protein flexibility. We have implemented many of the findings and refinements reported here into a web server that allows facile, automated predictions of model-free order parameters, MD RMSF and NMR RMSD values directly from backbone 1H, 13C and 15N chemical shift assignments. The server is available at http://wishart.biology.ualberta.ca/rci.
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Affiliation(s)
- Mark V Berjanskii
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada
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4
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Jarymowycz VA, Stone MJ. Fast time scale dynamics of protein backbones: NMR relaxation methods, applications, and functional consequences. Chem Rev 2007; 106:1624-71. [PMID: 16683748 DOI: 10.1021/cr040421p] [Citation(s) in RCA: 309] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Virginia A Jarymowycz
- Department of Chemistry and Interdisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405-0001, USA
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5
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Mokranjac D, Bourenkov G, Hell K, Neupert W, Groll M. Structure and function of Tim14 and Tim16, the J and J-like components of the mitochondrial protein import motor. EMBO J 2006; 25:4675-85. [PMID: 16977310 PMCID: PMC1590002 DOI: 10.1038/sj.emboj.7601334] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Accepted: 08/16/2006] [Indexed: 11/09/2022] Open
Abstract
The import motor of the mitochondrial translocase of the inner membrane (TIM23) mediates the ATP-dependent translocation of preproteins into the mitochondrial matrix by cycles of binding to and release from mtHsp70. An essential step of this process is the stimulation of the ATPase activity of mtHsp70 performed by the J cochaperone Tim14. Tim14 forms a complex with the J-like protein Tim16. The crystal structure of this complex shows that the conserved domains of the two proteins have virtually identical folds but completely different surfaces enabling them to perform different functions. The Tim14-Tim16 dimer reveals a previously undescribed arrangement of J and J-like domains. Mutations that destroy the complex between Tim14 and Tim16 are lethal demonstrating that complex formation is an essential requirement for the viability of cells. We further demonstrate tight regulation of the cochaperone activity of Tim14 by Tim16. The first crystal structure of a J domain in complex with a regulatory protein provides new insights into the function of the mitochondrial TIM23 translocase and the Hsp70 chaperone system in general.
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Affiliation(s)
- Dejana Mokranjac
- Institute for Physiological Chemistry, Ludwig-Maximilians University, Munich, Germany
| | - Gleb Bourenkov
- Max-Planck-Group for Structural Molecular Biology at DESY, Hamburg, Germany
| | - Kai Hell
- Institute for Physiological Chemistry, Ludwig-Maximilians University, Munich, Germany
| | - Walter Neupert
- Institute for Physiological Chemistry, Ludwig-Maximilians University, Munich, Germany
| | - Michael Groll
- Institute for Physiological Chemistry, Ludwig-Maximilians University, Munich, Germany
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6
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Stopar D, Strancar J, Spruijt RB, Hemminga MA. Motional restrictions of membrane proteins: a site-directed spin labeling study. Biophys J 2006; 91:3341-8. [PMID: 16905615 PMCID: PMC1614470 DOI: 10.1529/biophysj.106.090308] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Site-directed mutagenesis was used to produce 27 single cysteine mutants of bacteriophage M13 major coat protein spanning the whole primary sequence of the protein. Single-cysteine mutants were labeled with nitroxide spin labels and incorporated into phospholipid bilayers with increasing acyl chain length. The SDSL is combined with ESR and CD spectroscopy. CD spectroscopy provided information about the overall protein conformation in different mismatching lipids. The spin label ESR spectra were analyzed in terms of a new spectral simulation approach based on hybrid evolutionary optimization and solution condensation. This method gives the residue-level free rotational space (i.e., the effective space within which the spin label can wobble) and the diffusion constant of the spin label attached to the protein. The results suggest that the coat protein has a large structural flexibility, which facilitates a stable protein-to-membrane association in lipid bilayers with various degrees of hydrophobic mismatch.
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Affiliation(s)
- David Stopar
- University of Ljubljana, Biotechnical Faculty, SI-1000 Ljubljana, Slovenia
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7
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Garimella R, Liu X, Qiao W, Liang X, Zuiderweg ERP, Riley MI, Van Doren SR. Hsc70 contacts helix III of the J domain from polyomavirus T antigens: addressing a dilemma in the chaperone hypothesis of how they release E2F from pRb. Biochemistry 2006; 45:6917-29. [PMID: 16734427 DOI: 10.1021/bi060411d] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hsc70's expected binding site on helix II of the J domain of T antigens appears to be blocked in its structure bound to tumor suppressor pRb. We used NMR to map where mammalian Hsc70 binds the J domain of murine polyomavirus T antigens (PyJ). The ATPase domain of Hsc70 unexpectedly has its biggest effects on the NMR peak positions of the C-terminal end of helix III of PyJ. The Hsc70 ATPase domain protects the C-terminal end of helix III of PyJ from an uncharged paramagnetic probe of chelated Gd(III), clearly suggesting the interface. Effects on the conserved HPD loop and helix II of PyJ are smaller. The NMR results are supported by a novel assay of Hsc70's ATP hydrolysis showing that mutations of surface residues in PyJ helix III impair PyJ-dependent stimulation of Hsc70 activity. Evolutionary trace analysis of J domains suggests that helix III usually may join helix II in contributing specificities for cognate hsp70s. Our novel evidence implicating helix III differs from evidence that Escherichia coli DnaK primarily affects helix II and the HPD loop of DnaJ. We find the pRb-binding fragment of E2F1 to be intrinsically unfolded and a good substrate for Hsc70 in vitro. This suggests that E2F1 could be a substrate for Hsc70 recruited by T antigen to an Rb family member. Importantly, our results strengthen the chaperone hypothesis for E2F release from an Rb family member by Hsc70 recruited by large T antigen. That is, it now appears that Hsc70 can freely access helix III and the HPD motif of large T antigen bound to an Rb family member.
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Affiliation(s)
- Ravindranath Garimella
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri 65211, USA
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8
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Xiao J, Kim LS, Graham TR. Dissection of Swa2p/auxilin domain requirements for cochaperoning Hsp70 clathrin-uncoating activity in vivo. Mol Biol Cell 2006; 17:3281-90. [PMID: 16687570 PMCID: PMC1483056 DOI: 10.1091/mbc.e06-02-0106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 04/17/2006] [Accepted: 04/27/2006] [Indexed: 11/11/2022] Open
Abstract
The auxilin family of J-domain proteins load Hsp70 onto clathrin-coated vesicles (CCVs) to drive uncoating. In vitro, auxilin function requires its ability to bind clathrin and stimulate Hsp70 ATPase activity via its J-domain. To test these requirements in vivo, we performed a mutational analysis of Swa2p, the yeast auxilin ortholog. Swa2p is a modular protein with three N-terminal clathrin-binding (CB) motifs, a ubiquitin association (UBA) domain, a tetratricopeptide repeat (TPR) domain, and a C-terminal J-domain. In vitro, clathrin binding is mediated by multiple weak interactions, but a Swa2p truncation lacking two CB motifs and the UBA domain retains nearly full function in vivo. Deletion of all CB motifs strongly abrogates clathrin disassembly but does not eliminate Swa2p function in vivo. Surprisingly, mutation of the invariant HPD motif within the J-domain to AAA only partially affects Swa2p function. Similarly, a TPR point mutation (G388R) causes a modest phenotype. However, Swa2p function is abolished when these TPR and J mutations are combined. The TPR and J-domains are not functionally redundant because deletion of either domain renders Swa2p nonfunctional. These data suggest that the TPR and J-domains collaborate in a bipartite interaction with Hsp70 to regulate its activity in clathrin disassembly.
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Affiliation(s)
- Jing Xiao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
| | - Leslie S. Kim
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634
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9
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Berjanskii MV, Wishart DS. A simple method to predict protein flexibility using secondary chemical shifts. J Am Chem Soc 2006; 127:14970-1. [PMID: 16248604 DOI: 10.1021/ja054842f] [Citation(s) in RCA: 346] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein motions play a critical role in many biological processes, such as enzyme catalysis, allosteric regulation, antigen-antibody interactions, and protein-DNA binding. NMR spectroscopy occupies a unique place among methods for investigating protein dynamics due to its ability to provide site-specific information about protein motions over a large range of time scales. However, most NMR methods require a detailed knowledge of the 3D structure and/or the collection of additional experimental data (NOEs, T1, T2, etc.) to accurately measure protein dynamics. Here we present a simple method based on chemical shift data that allows accurate, quantitative, site-specific mapping of protein backbone mobility without the need of a three-dimensional structure or the collection and analysis of NMR relaxation data. Further, we show that this chemical shift method is able to quantitatively predict per-residue RMSD values (from both MD simulations and NMR structural ensembles) as well as model-free backbone order parameters.
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Affiliation(s)
- Mark V Berjanskii
- Departments of Computing Science and Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E8
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10
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Ding Z, Lee GI, Liang X, Gallazzi F, Arunima A, Van Doren SR. PhosphoThr peptide binding globally rigidifies much of the FHA domain from Arabidopsis receptor kinase-associated protein phosphatase. Biochemistry 2005; 44:10119-34. [PMID: 16042389 PMCID: PMC2813517 DOI: 10.1021/bi050414a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A net increase in the backbone rigidity of the kinase-interacting FHA domain (KI-FHA) from the Arabidopsis receptor kinase-associated protein phosphatase (KAPP) accompanies the binding of a phosphoThr peptide from its CLV1 receptor-like kinase partner, according to (15)N NMR relaxation at 11.7 and 14.1 T. All of the loops of free KI-FHA display evidence of nanosecond-scale motions. Many of these same residues have residual dipolar couplings that deviate from structural predictions. Binding of the CLV1 pT868 peptide seems to reduce nanosecond-scale fluctuations of all loops, including half of the residues of recognition loops. Residues important for affinity are found to be rigid, i.e., conserved residues and residues of the subsite for the key pT+3 peptide position. This behavior parallels SH2 and PTB domain recognition of pTyr peptides. PhosphoThr peptide binding increases KI-FHA backbone rigidity (S(2)) of three recognition loops, a loop nearby, seven strands from the beta-sandwich, and a distal loop. Compensating the trend of increased rigidity, binding enhances fast mobility at a few sites in four loops on the periphery of the recognition surface and in two loops on the far side of the beta-sandwich. Line broadening evidence of microsecond- to millisecond-scale fluctuations occurs across the six-stranded beta-sheet and nearby edges of the beta-sandwich; this forms a network connected by packing of interior side chains and H-bonding. A patch of the slowly fluctuating residues coincides with the site of segment-swapped dimerization in crystals of the FHA domain of human Chfr. Phosphopeptide binding introduces microsecond- to millisecond-scale fluctuations to more residues of the long 8/9 recognition loop of KI-FHA. The rigidity of this FHA domain appears to couple as a whole to pThr peptide binding.
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Affiliation(s)
| | | | - Xiangyang Liang
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri, 65211
| | - Fabio Gallazzi
- Molecular Biology Program, 125 Chemistry, 601 S. College Ave., University of Missouri, Columbia, Missouri, 65211 USA
| | - A. Arunima
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri, 65211
| | - Steven R. Van Doren
- To whom correspondence should be addressed, E-mail: , Phone: 1 (573) 882-5113, FAX: 1 (573) 884-4812
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11
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Hennessy F, Nicoll WS, Zimmermann R, Cheetham ME, Blatch GL. Not all J domains are created equal: implications for the specificity of Hsp40-Hsp70 interactions. Protein Sci 2005; 14:1697-709. [PMID: 15987899 PMCID: PMC2253343 DOI: 10.1110/ps.051406805] [Citation(s) in RCA: 216] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Heat shock protein 40s (Hsp40s) and heat shock protein 70s (Hsp70s) form chaperone partnerships that are key components of cellular chaperone networks involved in facilitating the correct folding of a broad range of client proteins. While the Hsp40 family of proteins is highly diverse with multiple forms occurring in any particular cell or compartment, all its members are characterized by a J domain that directs their interaction with a partner Hsp70. Specific Hsp40-Hsp70 chaperone partnerships have been identified that are dedicated to the correct folding of distinct subsets of client proteins. The elucidation of the mechanism by which these specific Hsp40-Hsp70 partnerships are formed will greatly enhance our understanding of the way in which chaperone pathways are integrated into finely regulated protein folding networks. From in silico analyses, domain swapping and rational protein engineering experiments, evidence has accumulated that indicates that J domains contain key specificity determinants. This review will critically discuss the current understanding of the structural features of J domains that determine the specificity of interaction between Hsp40 proteins and their partner Hsp70s. We also propose a model in which the J domain is able to integrate specificity and chaperone activity.
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Affiliation(s)
- Fritha Hennessy
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, South Africa
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12
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Verma CS, Fischer S. Protein stability and ligand binding: new paradigms from in-silico experiments. Biophys Chem 2005; 115:295-302. [PMID: 15752621 DOI: 10.1016/j.bpc.2004.12.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 11/26/2004] [Accepted: 12/10/2004] [Indexed: 10/26/2022]
Abstract
Computer simulations are used to investigate two features of proteins: ligand binding and ligand entry/exit. Both reveal surprising new insights into the physics of such complex systems and suggest at possible interpretations that depart from the usual paradigms. A ligand binding study using normal mode analysis suggests that, contrary to the perceived notion that ligand binding induces a tightening of the protein (as would be evidenced by a blue shift in its vibrational spectrum), there seem to be cases where ligand binding causes an increase in the entropy through a red-shift in the vibrational spectrum of the protein; this occurs in the part of the spectrum that is associated with large-scale low-frequency delocalized motions of proteins. Moreover, this increase seems to be dependent on the ability of the ligand to form hydrogen bonds within the polar cavity of the protein. This suggests an additional driving force for stabilizing complex formation. In parallel, pathways of ligand access to cavities in two proteins are mapped and it is found that, in agreement with recent interpretations of experimental data emerging from NMR studies, these pathways are characterized by a ruggedness of the energy landscape, which leads to a picture that has a physically more appealing basis than the traditional two-state paradigm normally invoked for ligand binding.
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Affiliation(s)
- Chandra S Verma
- Bioinformatics Institute, Matrix, Singapore-138671, Singapore.
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13
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Déméné H, Granier S, Muller D, Guillon G, Dufour MN, Delsuc MA, Hibert M, Pascal R, Mendre C. Active peptidic mimics of the second intracellular loop of the V(1A) vasopressin receptor are structurally related to the second intracellular rhodopsin loop: a combined 1H NMR and biochemical study. Biochemistry 2003; 42:8204-13. [PMID: 12846569 DOI: 10.1021/bi027358n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vasopressin (VP) receptors belong to the widespread G protein-coupled receptor family. The crucial role of VP receptor intracellular loops in the coupling with the heterotrimeric G proteins was previously demonstrated by construction of a vasopressin receptor chimera. Yet, no fine structural data are available concerning the receptor molecular determinants involved in their interactions with G proteins. In this study, we synthesized both a linear and a cyclic form of the second intracellular loop (i2) of the human V(1a) vasopressin receptor isoform that is important for the interaction between the alphaq/alpha11 G protein and the receptor. These two peptides are biologically active. They specifically inhibit vasopressin binding to the V(1a) receptor, suggesting that the corresponding endogenous peptides contribute to the structure of the vasopressin binding site via intra- or intermolecular interactions with the core of the V(1a) receptor. The i2 peptide structures were determined by (1)H NMR. Both exhibit a helix and helical elements in their N- and C-terminal parts, respectively, separated by a turn imposed by a proline residue. More interestingly, the central Pro-Leu motif conserved in many GPCRs and thought to be important for coupling to G proteins can adopt different conformations. The "U" shape structure of the i2 loop is compatible with its anchoring to transmembrane domains III and IV and is very similar to the shape of bovine rhodopsin i2. Altogether, these data contribute to a better understanding of the structure of a not yet crystallized GPCR using the mimetic peptide approach.
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Affiliation(s)
- Hélène Déméné
- Centre de Biochimie Structurale, UMR 5048 CNRS-UM1/UMR 554 INSERM-UM1, 29, rue de Navacelles, 34060 Montpellier Cedex, France
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14
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Landry SJ. Structure and energetics of an allele-specific genetic interaction between dnaJ and dnaK: correlation of nuclear magnetic resonance chemical shift perturbations in the J-domain of Hsp40/DnaJ with binding affinity for the ATPase domain of Hsp70/DnaK. Biochemistry 2003; 42:4926-36. [PMID: 12718534 DOI: 10.1021/bi027070y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular chaperone machine composed of Escherichia coli Hsp70/DnaK and Hsp40/DnaJ binds and releases client proteins in cycles of ATP-dependent protein folding, membrane translocation, disassembly, and degradation. The J-domain of DnaJ simultaneously stimulates ATP hydrolysis in the ATPase domain and capture of the client protein in the peptide-binding domain of DnaK. ATP-dependent binding of DnaJ to DnaK mimics DnaJ-dependent capture of a client protein. The dnaJ mutation that replaces aspartate-35 with asparagine (D35N) in the J-domain causes a defect in binding of DnaJ to DnaK. The dnaK mutation that replaces arginine-167 with alanine (R167A) in the ATPase domain of DnaK(R167A) restores binding of DnaJ(D35N). This genetic interaction was said to be allele-specific because wild-type DnaJ does not bind to DnaK(R167A). The J-domain of DnaJ binds to the ATPase domain of DnaK in its capacity as modulator of DnaK ATPase activity and conformational behavior. Surprisingly, the mutations affect the domainwise interaction in an almost opposite manner. D35N increases the affinity of the J-domain for the ATPase domain. R167A has no affect on the affinity of the ATPase domain for the D35N mutant J-domain, but it reduces the affinity for the wild-type J-domain. Previous amide ((1)H, (15)N) NMR chemical shift perturbation mapping in the J-domain suggested that the ATPase domain binds to J-domain helix II and the flanking loops. In the D35N mutant J-domain, chemical shift perturbations include additional effects at amides in the flexible loop II-III and helix III, which have been proposed to undergo an induced fit conformational change upon binding to DnaK. The integrated magnitudes of chemical shift perturbations for the various J-domain and ATPase domain pairs correlate with the free energies of binding. Thus, the J-domain structure can be described as a dynamic ensemble of conformations that is constrained by binding to the ATPase domain. J-domain helix II bends upon binding to the ATPase domain. D35N increases helix II bending, but less so in combination with R167A in the ATPase domain. Taken together, the results suggest that D35N overstabilizes an induced fit conformational change in loop II-III and helix III that is necessary for the J-domain to couple ATP hydrolysis with a conformational change in DnaK, and R167A destabilizes the induced conformation. Conclusions from this work have implications for understanding mechanisms of protein-protein interaction that are involved in allosteric regulation and genetic suppression.
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Affiliation(s)
- Samuel J Landry
- Department of Biochemistry, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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