1
|
Khoder-Agha F, Dias JM, Comisso M, Mirande M. Characterization of association of human mitochondrial lysyl-tRNA synthetase with HIV-1 Pol and tRNA 3Lys. BMC BIOCHEMISTRY 2018; 19:2. [PMID: 29562886 PMCID: PMC5863373 DOI: 10.1186/s12858-018-0092-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 03/14/2018] [Indexed: 11/21/2022]
Abstract
Background An important step in human immunodeficiency virus type 1 (HIV-1) replication is the packaging of tRNA3Lys from the host cell, which plays the role of primer RNA in the process of initiation of reverse transcription. The viral GagPol polyprotein precursor, and the human mitochondrial lysyl-tRNA synthetase (mLysRS) from the host cell, have been proposed to be involved in the packaging process. More specifically, the catalytic domain of mLysRS is supposed to interact with the transframe (TF or p6*) and integrase (IN) domains of the Pol region of the GagPol polyprotein. Results In this work, we report a quantitative characterization of the protein:protein interactions between mLysRS and its viral partners, the Pol polyprotein, and the isolated integrase and transframe domains of Pol. A dissociation constant of 1.3 ± 0.2 nM was determined for the Pol:mLysRS interaction, which exemplifies the robustness of this association. The protease and reverse transcriptase domains of GagPol are dispensable in this association, but the TF and IN domains have to be connected by a linker polypeptide to recapitulate a high affinity partner for mLysRS. The binding of the viral proteins to mLysRS does not dramatically enhance the binding affinity of mLysRS for tRNA3Lys. Conclusions These data support the conclusion that the complex formed between GagPol, mLysRS and tRNA3Lys, which involves direct interactions between the IN and TF domains of Pol with mLysRS, is more robust than suggested by the previous models supposed to be involved in the packaging of tRNA3Lys into HIV-1 particles.
Collapse
Affiliation(s)
- Fawzi Khoder-Agha
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - José M Dias
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Martine Comisso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Marc Mirande
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
| |
Collapse
|
2
|
Takagi S, Momose F, Morikawa Y. FRET analysis of HIV-1 Gag and GagPol interactions. FEBS Open Bio 2017; 7:1815-1825. [PMID: 29123989 PMCID: PMC5666392 DOI: 10.1002/2211-5463.12328] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 11/26/2022] Open
Abstract
The Gag protein of HIV multimerizes to form viral particles. The GagPol protein encoding virus‐specific enzymes, such as protease, reverse transcriptase, and integrase, is incorporated into HIV particles via interactions with Gag. The catalytically active forms of these enzymes are dimeric or tetrameric. We employed Förster resonance energy transfer (FRET) assays to evaluate Gag–Gag, Gag–GagPol, and GagPol–GagPol interactions and investigated Gag and Pol interdomains tolerant to fluorescent protein insertion for FRET assays. Our data indicated that the matrix (MA)–capsid (CA) domain junction in the Gag region and the Gag C terminus were equally available for Gag–Gag and Gag–GagPol interaction assays. For GagPol dimerization assays, insertion at the MA–CA domain junction was most favorable.
Collapse
Affiliation(s)
- Shimon Takagi
- Kitasato Institute for Life Sciences and Graduate School for Infection Control Kitasato University Tokyo Japan.,Present address: A2 Healthcare Corporation Sumitomo Fudosan Korakuen Bldg., Koishikawa 1-4-1, Bunkyo-ku Tokyo 112-0002 Japan
| | - Fumitaka Momose
- Kitasato Institute for Life Sciences and Graduate School for Infection Control Kitasato University Tokyo Japan
| | - Yuko Morikawa
- Kitasato Institute for Life Sciences and Graduate School for Infection Control Kitasato University Tokyo Japan
| |
Collapse
|
3
|
Joachimiak LA, Walzthoeni T, Liu CW, Aebersold R, Frydman J. The structural basis of substrate recognition by the eukaryotic chaperonin TRiC/CCT. Cell 2015; 159:1042-1055. [PMID: 25416944 DOI: 10.1016/j.cell.2014.10.042] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 08/17/2014] [Accepted: 10/20/2014] [Indexed: 12/20/2022]
Abstract
The eukaryotic chaperonin TRiC (also called CCT) is the obligate chaperone for many essential proteins. TRiC is hetero-oligomeric, comprising two stacked rings of eight different subunits each. Subunit diversification from simpler archaeal chaperonins appears linked to proteome expansion. Here, we integrate structural, biophysical, and modeling approaches to identify the hitherto unknown substrate-binding site in TRiC and uncover the basis of substrate recognition. NMR and modeling provided a structural model of a chaperonin-substrate complex. Mutagenesis and crosslinking-mass spectrometry validated the identified substrate-binding interface and demonstrate that TRiC contacts full-length substrates combinatorially in a subunit-specific manner. The binding site of each subunit has a distinct, evolutionarily conserved pattern of polar and hydrophobic residues specifying recognition of discrete substrate motifs. The combinatorial recognition of polypeptides broadens the specificity of TRiC and may direct the topology of bound polypeptides along a productive folding trajectory, contributing to TRiC's unique ability to fold obligate substrates.
Collapse
Affiliation(s)
- Lukasz A Joachimiak
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305, USA.
| | - Thomas Walzthoeni
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland; Ph.D. Program in Molecular Life Sciences, University of Zurich/ETH Zurich, 8057 Zurich, Switzerland
| | - Corey W Liu
- Stanford Magnetic Resonance Laboratory, Stanford University, Stanford, CA 94305, USA
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland; Faculty of Science, University of Zurich, 8006 Zurich, Switzerland
| | - Judith Frydman
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
4
|
Efavirenz enhances HIV-1 gag processing at the plasma membrane through Gag-Pol dimerization. J Virol 2013; 87:3348-60. [PMID: 23302874 DOI: 10.1128/jvi.02306-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Efavirenz (EFV), a nonnucleoside reverse transcriptase (RT) inhibitor, also inhibits HIV-1 particle release through enhanced Gag/Gag-Pol processing by protease (PR). To better understand the mechanisms of the EFV-mediated enhancement of Gag processing, we examined the intracellular localization of Gag/Gag-Pol processing products and their precursors. Confocal microscopy revealed that in the presence of EFV, the N-terminal p17 matrix (p17MA) fragment was uniformly distributed at the plasma membrane (PM) but the central p24 capsid (p24CA) and the Pol-encoded RT antigens were diffusely distributed in the cytoplasm, and all of the above were observed in puncta at the PM in the absence of EFV. EFV did not impair PM targeting of Gag/Gag-Pol precursors. Membrane flotation analysis confirmed these findings. Such uniform distribution of p17MA at the PM was not seen by overexpression of Gag-Pol and was suppressed when EFV-resistant HIV-1 was used. Forster's fluorescence resonance energy transfer assay revealed that Gag-Pol precursor dimerization occurred mainly at the PM and that EFV induced a significant increase of the Gag-Pol dimerization at the PM. Gag-Pol dimerization was not enhanced when HIV-1 contained the EFV resistance mutation in RT. Bacterial two-hybrid assay showed that EFV enhanced the dimerization of PR-RT fragments and restored the dimerization impaired by the dimerization-defective mutation in the RT tryptophan repeat motif but not that impaired by the mutation at the PR dimer interface. Collectively, our data indicate that EFV enhances Gag-Pol precursor dimerization, likely after PM targeting but before complete particle assembly, resulting in uniform distribution of p17MA to and dissociation of p24CA and RT from the PM.
Collapse
|
5
|
Aspects of HIV-1 assembly that promote primer tRNALys3 annealing to viral RNA. Virus Res 2012; 169:340-8. [DOI: 10.1016/j.virusres.2012.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 05/25/2012] [Accepted: 06/01/2012] [Indexed: 01/30/2023]
|
6
|
Xue B, Mizianty MJ, Kurgan L, Uversky VN. Protein intrinsic disorder as a flexible armor and a weapon of HIV-1. Cell Mol Life Sci 2012; 69:1211-59. [PMID: 22033837 PMCID: PMC11114566 DOI: 10.1007/s00018-011-0859-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/28/2011] [Accepted: 10/03/2011] [Indexed: 01/19/2023]
Abstract
Many proteins and protein regions are disordered in their native, biologically active states. These proteins/regions are abundant in different organisms and carry out important biological functions that complement the functional repertoire of ordered proteins. Viruses, with their highly compact genomes, small proteomes, and high adaptability for fast change in their biological and physical environment utilize many of the advantages of intrinsic disorder. In fact, viral proteins are generally rich in intrinsic disorder, and intrinsically disordered regions are commonly used by viruses to invade the host organisms, to hijack various host systems, and to help viruses in accommodation to their hostile habitats and to manage their economic usage of genetic material. In this review, we focus on the structural peculiarities of HIV-1 proteins, on the abundance of intrinsic disorder in viral proteins, and on the role of intrinsic disorder in their functions.
Collapse
Affiliation(s)
- Bin Xue
- Department of Molecular Medicine, University of South Florida, College of Medicine, 12901 Bruce B. Downs Blvd, MDC07, Tampa, FL 33612 USA
| | - Marcin J. Mizianty
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 Canada
| | - Lukasz Kurgan
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 Canada
| | - Vladimir N. Uversky
- Department of Molecular Medicine, University of South Florida, College of Medicine, 12901 Bruce B. Downs Blvd, MDC07, Tampa, FL 33612 USA
- Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region Russia
| |
Collapse
|
7
|
Agniswamy J, Sayer JM, Weber IT, Louis JM. Terminal interface conformations modulate dimer stability prior to amino terminal autoprocessing of HIV-1 protease. Biochemistry 2012; 51:1041-50. [PMID: 22242794 PMCID: PMC3287067 DOI: 10.1021/bi201809s] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The HIV-1 protease (PR) mediates its own release (autoprocessing) from the polyprotein precursor, Gag-Pol, flanked by the transframe region (TFR) and reverse transcriptase at its N- and C-termini, respectively. Autoprocessing at the N-terminus of PR mediates stable dimer formation essential for catalytic activity, leading to the formation of infectious virus. An antiparallel β-sheet interface formed by the four N- and C-terminal residues of each subunit is important for dimer stability. Here, we present the first high-resolution crystal structures of model protease precursor-clinical inhibitor (PI darunavir or saquinavir) complexes, revealing varying conformations of the N-terminal flanking (S(-4)FNF(-1)) and interface residues (P(1)QIT(4)). A 180° rotation of the T(4)-L(5) peptide bond is accompanied by a new Q(2)-L(5) hydrogen bond and complete disengagement of PQIT from the β-sheet dimer interface, which may be a feature for intramolecular autoprocessing. This result is consistent with drastically lower thermal stability by 14-20 °C of PI complexes of precursors and the mature PR lacking its PQIT residues (by 18.3 °C). Similar to the TFR-PR precursor, this deletion also results in a darunavir dissociation constant (2 × 10(4))-fold higher and a markedly increased dimer dissociation constant relative to the mature PR. The terminal β-sheet perturbations of the dimeric structure likely account for the drastically poorer inhibition of autoprocessing of TFR-PR relative to the mature PR, even though significant differences in active site-PI interactions in these structures were not observed. The novel conformations of the dimer interface may be exploited to target selectively the protease precursor prior to its N-terminal cleavage.
Collapse
Affiliation(s)
- Johnson Agniswamy
- Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA30303
| | - Jane M. Sayer
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland 20892
| | - Irene T. Weber
- Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA30303
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, Maryland 20892
| |
Collapse
|
8
|
Jesus da Costa L, Lopes Dos Santos A, Mandic R, Shaw K, Santana de Aguiar R, Tanuri A, Luciw PA, Peterlin BM. Interactions between SIVNef, SIVGagPol and Alix correlate with viral replication and progression to AIDS in rhesus macaques. Virology 2009; 394:47-56. [PMID: 19748111 DOI: 10.1016/j.virol.2009.08.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Revised: 05/26/2009] [Accepted: 08/12/2009] [Indexed: 11/25/2022]
Abstract
Infection with Simian Immunodeficiency Virus (SIV) leads to high viral loads and progression to Simian AIDS (SAIDS) in rhesus macaques. The viral accessory protein Nef is required for this phenotype in monkeys as well as in HIV-infected humans. Previously, we determined that HIVNef binds HIVGagPol and Alix for optimal viral replication in cells. In this study, we demonstrated that these interactions could correlate with high viral loads leading to SAIDS in the infected host. By infecting rhesus macaques with a mutant SIV(mac239), where sequences in the nef gene that are required for these interactions were mutated, we observed robust viral replication and disease in two out of four monkeys, where they reverted to the wild type genotype and phenotype. These two rhesus macaques also died of SAIDS. Two other monkeys did not progress to disease and continued to harbor mutant nef sequences. We conclude that interactions between Nef, GagPol and Alix contribute to optimal viral replication and progression to disease in the infected host.
Collapse
|
9
|
Uncoupling human immunodeficiency virus type 1 Gag and Pol reading frames: role of the transframe protein p6* in viral replication. J Virol 2009; 83:7210-20. [PMID: 19403679 DOI: 10.1128/jvi.02603-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apart from its regulatory role in protease (PR) activation, little is known about the function of the human immunodeficiency virus type 1 transframe protein p6* in the virus life cycle. p6* is located between the nucleocapsid and PR domains in the Gag-Pol polyprotein precursor and is cleaved by PR during viral maturation. We have recently reported that the central region of p6* can be extensively mutated without abolishing viral infectivity and replication in vitro. However, mutagenesis of the entire p6*-coding sequence in the proviral context is not feasible without affecting the superimposed frameshift signal or the overlapping p1-p6(gag) sequences. To overcome these limitations, we created a novel NL4-3-derived provirus by displacing the original frameshift signal to the 3' end of the gag gene, thereby uncoupling the p6* gene sequence from the p1-p6(gag) reading frame. The resulting virus (AL) proved to be replication competent in different cell cultures and thus represents an elegant tool for detailed analysis of p6* function. Hence, extensive deletions or substitutions were introduced into the p6* gene sequence of the AL provirus, and effects on particle release, protein processing, and viral infectivity were evaluated. Interestingly, neither the deletion of 63% of all p6* residues nor the partial substitution by a heterologous sequence affected virus growth and infectivity, suggesting that p6* is widely dispensable for viral in vitro replication. However, the insertion of a larger reporter sequence interfered with virus production and maturation, implying that the length or conformation of this spacer region might be critical for p6* function.
Collapse
|
10
|
Leiherer A, Ludwig C, Wagner R. Influence of extended mutations of the HIV-1 transframe protein p6 on Nef-dependent viral replication and infectivity in vitro. Virology 2009; 387:200-10. [PMID: 19269660 DOI: 10.1016/j.virol.2009.01.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 01/06/2009] [Accepted: 01/29/2009] [Indexed: 11/15/2022]
Abstract
The HIV-1 transframe protein p6 known to modulate HIV-1 protease activation has been suggested to interact with the viral pathogenicity factor Nef. However, a potential interaction site in p6 has not been mapped so far. To evaluate effects of p6 modification on viral replication in light of Nef function, clustered substitutions were introduced into the central p6 region of the infectious provirus NL4-3 and virus growth and composition of the various mutants was analyzed in different cell cultures in the presence or absence of Nef. Whereas clustered p6 substitutions did neither affect particle incorporation of Nef, nor precursor maturation or viral infectivity, a simultaneous substitution of 40 of the total 56 p6 residues significantly diminished viral infectivity and replication in a Nef-independent manner. Furthermore, this extended modification was not capable of rescuing the negative effects of a transdominant Nef mutant on particle production suggesting that the proposed target for Nef interaction in Gag-Pol is located outside the modified p6 region. In sum these data strongly argue against a functional connection of the central p6 region and Nef during viral life cycle.
Collapse
Affiliation(s)
- Andreas Leiherer
- Molecular Microbiology and Gene Therapy, Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Straubeta Allee 11, D-93053 Regensburg, Germany
| | | | | |
Collapse
|
11
|
Importance of protease cleavage sites within and flanking human immunodeficiency virus type 1 transframe protein p6* for spatiotemporal regulation of protease activation. J Virol 2008; 82:4573-84. [PMID: 18321978 DOI: 10.1128/jvi.02353-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) protease (PR) has recently been shown to be inhibited by its propeptide p6* in vitro. As p6* itself is a PR substrate, the primary goal of this study was to determine the importance of p6* cleavage for HIV-1 maturation and infectivity. For that purpose, short peptide variants mimicking proposed cleavage sites within and flanking p6* were designed and analyzed for qualitative and quantitative hydrolysis in vitro. Proviral clones comprising the selected cleavage site mutations were established and analyzed for Gag and Pol processing, virus maturation, and infectivity in cultured cells. Amino-terminal cleavage site mutation caused aberrant processing of nucleocapsid proteins and delayed replication kinetics. Blocking the internal cleavage site resulted in the utilization of a flanking site at a significantly decreased hydrolysis rate in vitro, which however did not affect Gag-Pol processing and viral replication. Although mutations blocking cleavage at the p6* carboxyl terminus yielded noninfectious virions exhibiting severe Gag processing defects, mutations retarding hydrolysis of this cleavage site neither seemed to impact viral infectivity and propagation in cultured cells nor seemed to interfere with overall maturation of released viruses. Interestingly, these mutants were shown to be clearly disadvantaged when challenged with wild-type virus in a dual competition assay. In sum, we conclude that p6* cleavage is absolutely essential to allow complete activation of the PR and subsequent processing of the viral precursors.
Collapse
|
12
|
Sayer JM, Liu F, Ishima R, Weber IT, Louis JM. Effect of the active site D25N mutation on the structure, stability, and ligand binding of the mature HIV-1 protease. J Biol Chem 2008; 283:13459-70. [PMID: 18281688 DOI: 10.1074/jbc.m708506200] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All aspartic proteases, including retroviral proteases, share the triplet DTG critical for the active site geometry and catalytic function. These residues interact closely in the active, dimeric structure of HIV-1 protease (PR). We have systematically assessed the effect of the D25N mutation on the structure and stability of the mature PR monomer and dimer. The D25N mutation (PR(D25N)) increases the equilibrium dimer dissociation constant by a factor >100-fold (1.3 +/- 0.09 microm) relative to PR. In the absence of inhibitor, NMR studies reveal clear structural differences between PR and PR(D25N) in the relatively mobile P1 loop (residues 79-83) and flap regions, and differential scanning calorimetric analyses show that the mutation lowers the stabilities of both the monomer and dimer folds by 5 and 7.3 degrees C, respectively. Only minimal differences are observed in high resolution crystal structures of PR(D25N) complexed to darunavir (DRV), a potent clinical inhibitor, or a non-hydrolyzable substrate analogue, Ac-Thr-Ile-Nle-r-Nle-Gln-Arg-NH(2) (RPB), as compared with PR.DRV and PR.RPB complexes. Although complexation with RPB stabilizes both dimers, the effect on their T(m) is smaller for PR(D25N) (6.2 degrees C) than for PR (8.7 degrees C). The T(m) of PR(D25N).DRV increases by only 3 degrees C relative to free PR(D25N), as compared with a 22 degrees C increase for PR.DRV, and the mutation increases the ligand dissociation constant of PR(D25N).DRV by a factor of approximately 10(6) relative to PR.DRV. These results suggest that interactions mediated by the catalytic Asp residues make a major contribution to the tight binding of DRV to PR.
Collapse
Affiliation(s)
- Jane M Sayer
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | | | | | | | | |
Collapse
|
13
|
Louis JM, Ishima R, Torchia DA, Weber IT. HIV-1 protease: structure, dynamics, and inhibition. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2007; 55:261-98. [PMID: 17586318 DOI: 10.1016/s1054-3589(07)55008-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | |
Collapse
|
14
|
Paulus C, Ludwig C, Wagner R. Contribution of the Gag-Pol transframe domain p6* and its coding sequence to morphogenesis and replication of human immunodeficiency virus type 1. Virology 2005; 330:271-83. [PMID: 15527852 DOI: 10.1016/j.virol.2004.09.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 08/19/2004] [Accepted: 09/13/2004] [Indexed: 10/26/2022]
Abstract
The human immunodeficiency virus type-1 (HIV-1) transframe domain p6* is located between the nucleocapsid protein (NC) and the protease (PR) within the Gag-Pol precursor. This flexible, 68-amino-acid HIV-1 p6* domain has been suggested to negatively interfere with HIV PR activity in vitro proposing a contribution of either the C-terminal p6* tetrapeptide, internal cryptic PR cleavage sites, or a zymogen-related mechanism to a regulated PR activation. To assess these hypotheses in the viral context, a series of recombinant HX10-based provirus constructs has been established with clustered amino acid substitutions throughout the entire p6* coding sequence. Comparative analysis of the mutant proviral clones in different cell culture systems revealed that mutations within the well-conserved amino-terminal p6* region modified the Gag/Gag-Pol ratio and thus resulted in the release of viruses with impaired infectivity. Clustered amino acid substitutions destroying (i) the predicted cryptic PR cleavage sites or (ii) homologies to the pepsinogen propeptide did not influence viral replication in cell culture, whereas substitutions of the carboxyl-terminal p6* residues 62 to 68 altering proper release of the mature PR from the Gag-Pol precursor drastically reduced viral infectivity. Thus, the critical contribution of p6* and overlapping cis-acting sequence elements to timely regulated virus maturation and infectivity is closely linked to precise ribosomal frameshifting and proper N-terminal release of the viral PR from the Gag-Pol precursor, clearly disproving the hypothesis that sequence motifs in the central part of p6* modulate PR activation and viral infectivity.
Collapse
Affiliation(s)
- Christina Paulus
- Institute of Medical Microbiology and Hygiene, D-93053 Regensburg, Germany
| | | | | |
Collapse
|
15
|
Chatterjee A, Mridula P, Mishra RK, Mittal R, Hosur RV. Folding Regulates Autoprocessing of HIV-1 Protease Precursor. J Biol Chem 2005; 280:11369-78. [PMID: 15632156 DOI: 10.1074/jbc.m412603200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autoprocessing of HIV-1 protease (PR) precursors is a crucial step in the generation of the mature protease. Very little is known regarding the molecular mechanism and regulation of this important process in the viral life cycle. In this context we report here the first and complete residue level investigations on the structural and folding characteristics of the 17-kDa precursor TFR-PR-C(nn) (161 residues) of HIV-1 protease. The precursor shows autoprocessing activity indicating that the solution has a certain population of the folded active dimer. Removal of the 5-residue extension, C(nn) at the C-terminal of PR enhanced the activity to some extent. However, NMR structural characterization of the precursor containing a mutation, D25N in the PR at pH 5.2 and 32 degrees C under different conditions of partial and complete denaturation by urea, indicate that the precursor has a high tendency to be unfolded. The major population in the ensemble displays some weak folding propensities in both the TFR and the PR regions, and many of these in the PR region are the non-native type. As both D25N mutant and wild-type PR are known to fold efficiently to the same native dimeric form, we infer that TFR cleavage enables removal of the non-native type of preferences in the PR domain to cause constructive folding of the protein. These results indicate that intrinsic structural and folding preferences in the precursor would have important regulatory roles in the autoprocessing reaction and generation of the mature enzyme.
Collapse
Affiliation(s)
- Amarnath Chatterjee
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
| | | | | | | | | |
Collapse
|
16
|
Ishima R, Torchia DA, Lynch SM, Gronenborn AM, Louis JM. Solution structure of the mature HIV-1 protease monomer: insight into the tertiary fold and stability of a precursor. J Biol Chem 2003; 278:43311-9. [PMID: 12933791 DOI: 10.1074/jbc.m307549200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We present the first solution structure of the HIV-1 protease monomer spanning the region Phe1-Ala95 (PR1-95). Except for the terminal regions (residues 1-10 and 91-95) that are disordered, the tertiary fold of the remainder of the protease is essentially identical to that of the individual subunit of the dimer. In the monomer, the side chains of buried residues stabilizing the active site interface in the dimer, such as Asp25, Asp29, and Arg87, are now exposed to solvent. The flap dynamics in the monomer are similar to that of the free protease dimer. We also show that the protease domain of an optimized precursor flanked by 56 amino acids of the N-terminal transframe region is predominantly monomeric, exhibiting a tertiary fold that is quite similar to that of PR1-95 structure. This explains the very low catalytic activity observed for the protease prior to its maturation at its N terminus as compared with the mature protease, which is an active stable dimer under identical conditions. Adding as few as 2 amino acids to the N terminus of the mature protease significantly increases its dissociation into monomers. Knowledge of the protease monomer structure and critical features of its dimerization may aid in the screening and design of compounds that target the protease prior to its maturation from the Gag-Pol precursor.
Collapse
Affiliation(s)
- Rieko Ishima
- Molecular Structural Biology Unit, NIDCR, National Institutes of Health, Bethesda, Maryland 20892-4307, USA
| | | | | | | | | |
Collapse
|
17
|
Dautin N, Karimova G, Ladant D. Human immunodeficiency virus (HIV) type 1 transframe protein can restore activity to a dimerization-deficient HIV protease variant. J Virol 2003; 77:8216-26. [PMID: 12857890 PMCID: PMC165233 DOI: 10.1128/jvi.77.15.8216-8226.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The protease (PR) from human immunodeficiency virus (HIV) is essential for viral replication: this aspartyl protease, active only as a dimer, is responsible for cleavage of the viral polyprotein precursors (Gag and Gag-Pol), to release the functional mature proteins. In this work, we have studied the structure-function relationships of the HIV PR by combining a genetic test to detect proteolytic activity in Escherichia coli and a bacterial two-hybrid assay to analyze PR dimerization. We showed that a drug-resistant PR variant isolated from a patient receiving highly active antiretroviral therapy is impaired in its dimerization capability and, as a consequence, is proteolytically inactive. We further showed that the polypeptide regions adjacent to the PR coding sequence in the Gag-Pol polyprotein precursor, and in particular, the transframe polypeptide (TF), located at the N terminus of PR, can facilitate the dimerization of this variant PR and restore its enzymatic activity. We propose that the TF protein could help to compensate for folding and/or dimerization defects in PR arising from certain mutations within the PR coding sequence and might therefore function to buffer genetic variations in PR.
Collapse
Affiliation(s)
- Nathalie Dautin
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, CNRS URA 2185, Institut Pasteur, 75724 Paris Cedex 15, France.
| | | | | |
Collapse
|
18
|
Hill MK, Shehu-Xhilaga M, Crowe SM, Mak J. Proline residues within spacer peptide p1 are important for human immunodeficiency virus type 1 infectivity, protein processing, and genomic RNA dimer stability. J Virol 2002; 76:11245-53. [PMID: 12388684 PMCID: PMC136739 DOI: 10.1128/jvi.76.22.11245-11253.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The full-length human immunodeficiency virus type 1 (HIV-1) mRNA encodes two precursor polyproteins, Gag and GagProPol. An infrequent ribosomal frameshifting event allows these proteins to be synthesized from the same mRNA in a predetermined ratio of 20 Gag proteins for each GagProPol. The RNA frameshift signal consists of a slippery sequence and a hairpin stem-loop whose thermodynamic stability has been shown in in vitro translation systems to be critical to frameshifting efficiency. In this study we examined the frameshift region of HIV-1, investigating the effects of altering stem-loop stability in the context of the complete viral genome and assessing the role of the Gag spacer peptide p1 and the GagProPol transframe (TF) protein that are encoded in this region. By creating a series of frameshift region mutants that systematically altered the stability of the frameshift stem-loop and the protein sequences of the p1 spacer peptide and TF protein, we have demonstrated the importance of stem-loop thermodynamic stability in frameshifting efficiency and viral infectivity. Multiple changes to the amino acid sequence of p1 resulted in altered protein processing, reduced genomic RNA dimer stability, and abolished viral infectivity. The role of the two highly conserved proline residues in p1 (position 7 and 13) was also investigated. Replacement of the two proline residues by leucines resulted in mutants with altered protein processing and reduced genomic RNA dimer stability that were also noninfectious. The unique ability of proline to confer conformational constraints on a peptide suggests that the correct folding of p1 may be important for viral function.
Collapse
MESH Headings
- Amino Acid Sequence
- Base Sequence
- Dimerization
- Frameshifting, Ribosomal
- Gene Products, gag/chemistry
- Gene Products, gag/genetics
- Gene Products, gag/metabolism
- Genome, Viral
- HIV Infections/virology
- HIV-1/genetics
- HIV-1/metabolism
- HIV-1/pathogenicity
- Humans
- Leukocytes, Mononuclear/virology
- Molecular Sequence Data
- Mutation
- Peptides/chemistry
- Peptides/genetics
- Peptides/metabolism
- Proline/chemistry
- Protein Processing, Post-Translational
- RNA Stability
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Viral/chemistry
- RNA, Viral/genetics
- Viral Proteins
- gag Gene Products, Human Immunodeficiency Virus
Collapse
Affiliation(s)
- Melissa K Hill
- AIDS Pathogenesis Research Unit, Macfarlane Burnet Institute for Medical Research and Public Health, Monash University, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
19
|
Chen N, Morag A, Almog N, Blumenzweig I, Dreazin O, Kotler M. Extended nucleocapsid protein is cleaved from the Gag-Pol precursor of human immunodeficiency virus type 1. J Gen Virol 2001; 82:581-590. [PMID: 11172099 DOI: 10.1099/0022-1317-82-3-581] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human immunodeficiency virus type 1 Gag and Gag-Pol precursors are translated from an mRNA which is indistinguishable from the full-length genomic RNA. The ratio of Gag to Gag-Pol polyproteins is approximately 20:1 and is controlled by a frameshift of the reading frame, which takes place downstream of the p7 nucleocapsid (NC) in the N terminus of the p1 peptide. The viral precursors Gag and Gag-Pol are cleaved by the virus-encoded protease (PR) into the structural proteins, and into p6(Pol), PR, reverse transcriptase and integrase. Due to the frameshift event, the cleavage site at the C terminus of NC coded in the Gag frame (ERQAN-FLGKI) changes either to ERQANFLRED or ERQANFFRED. The results presented in this report demonstrate that the NC released from the Gag-Pol precursor is 8 amino acid residues longer than the NC cleaved from the Gag polyprotein. Our results also show that truncated Gag-Pol precursors bearing cleavage site mutation at the NC/p6(Pol), and/or p6(Pol)/PR junctions, undergo autoprocessing in bacterial and eukaryotic cells, indicating that PR is active when part of the precursor.
Collapse
Affiliation(s)
- Nissim Chen
- Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel
| | - Abraham Morag
- Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel
| | - Nava Almog
- Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel
| | - Immanuel Blumenzweig
- Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel
| | - Orna Dreazin
- National Public Health Laboratories, Ministry of Health, Israel3
| | - Moshe Kotler
- Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel
| |
Collapse
|
20
|
Louis JM, Weber IT, Tözsér J, Clore GM, Gronenborn AM. HIV-1 protease: maturation, enzyme specificity, and drug resistance. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2001; 49:111-46. [PMID: 11013762 DOI: 10.1016/s1054-3589(00)49025-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- J M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes, Bethesda, Maryland 20892-0580, USA
| | | | | | | | | |
Collapse
|
21
|
Asakura T, Matsumoto I, Funaki J, Arai S, Abe K. The plant aspartic proteinase-specific polypeptide insert is not directly related to the activity of oryzasin 1. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5115-22. [PMID: 10931195 DOI: 10.1046/j.1432-1327.2000.01582.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many plant aspartic proteinases (APs) are different from animal and microbial APs in that they contain a polypeptide insert, approximately 100 amino acids in length, in the C-terminal region. To interpret the significance of this insert, we constructed an expression system for rice AP oryzasin 1 by linking a pro-oryzasin 1 downstream of glutathione S-transferase (GST). GST-proOS1 expressed the highest degree of hemoglobin-hydrolytic activity when treated at pH 3.3 and incubated for 24 h at room temperature. We carried out a similar experiment using an insert-lacking proOS1 mutant, GST-DeltaproOS1, as the fusion protein, and found it to show similar activity. This result indicates that the insert is not involved in the production of AP activity. We then investigated the autolysis of the two proteins by Western blot analysis. GST-proOS1 was autolyzed into 67- and 64-kDa fragments, while GST-DeltaproOS1 autolyzed to 54- and 52-kDa products. GST-DeltaproOS1 clearly produced two molecular species early in the autolytic process, and not later than 3 h from the start, but no such clear result was observed in the case of GST-proOS1. This suggests that, although the presence of the plant AP-specific insert does not influence the enzyme activity by itself, it apparently has an effect on the autolysis of OS1.
Collapse
Affiliation(s)
- T Asakura
- Laboratory of Food Science, Atomi Junior College, Tokyo, Japan
| | | | | | | | | |
Collapse
|
22
|
Louis JM, Wondrak EM, Kimmel AR, Wingfield PT, Nashed NT. Proteolytic processing of HIV-1 protease precursor, kinetics and mechanism. J Biol Chem 1999; 274:23437-42. [PMID: 10438521 DOI: 10.1074/jbc.274.33.23437] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously it was demonstrated using a model precursor that processing at the N terminus of the HIV-1 protease (PR) precedes processing at its C terminus. We now show the expression, purification, and kinetics of the autoprocessing reaction of a PR precursor linked to 53 amino acids of the native flanking transframe region (DeltaTFP-p6(pol)) of Gag-Pol and containing its two native cleavage sites. The PR contains the two cysteine residues exchanged to alanines, mutations that do not alter the kinetics or the structural stability of the mature PR. DeltaTFP-p6(pol)-PR, which encompasses the known PR inhibitor sequence Glu-Asp-Leu within DeltaTFP, undergoes cleavage at the DeltaTFP/p6(pol) and p6(pol)/PR sites in two consecutive steps to produce the mature PR. Both DeltaTFP-p6(pol)-PR and p6(pol)-PR exhibit low intrinsic enzymatic activity. The appearance of the mature PR is accompanied by a large increase in catalytic activity. It follows first-order kinetics in protein concentration with a rate constant of 0.13 +/- 0.01 min(-1) in 0.1 M acetate at pH 4.8. The pH-rate profile for the observed first-order rate constant is bell-shaped with two ionizable groups of pK(a) 4.9 and 5.1. The rate constant also exhibits approximately 7-fold higher sensitivity to urea denaturation as compared with that of the mature PR, suggesting that the cleavage at the N terminus of the PR domain from the precursor leads to the stabilization of the dimeric structure.
Collapse
Affiliation(s)
- J M Louis
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0580, USA.
| | | | | | | | | |
Collapse
|
23
|
Paulus C, Hellebrand S, Tessmer U, Wolf H, Kräusslich HG, Wagner R. Competitive inhibition of human immunodeficiency virus type-1 protease by the Gag-Pol transframe protein. J Biol Chem 1999; 274:21539-43. [PMID: 10419458 DOI: 10.1074/jbc.274.31.21539] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human immunodeficiency virus type-1 (HIV-1) transframe protein p6* is located between the structural and enzymatic domains of the Gag-Pol polyprotein, flanked by the nucleocapsid (NC) and the protease (PR) domain at its amino and carboxyl termini, respectively. Here, we report that recombinant highly purified HIV-1 p6* specifically inhibits mature HIV-1 PR activity. Kinetic analyses and cross-linking experiments revealed a competitive mechanism for PR inhibition by p6*. We further demonstrate that the four carboxyl-terminal residues of p6* are essential but not sufficient for p6*-mediated inhibition of PR activity. Based on these results, we suggest a role of the transframe protein p6* in regulating HIV-1 PR activity during viral replication.
Collapse
Affiliation(s)
- C Paulus
- Institut für Medizinische Mikrobiologie und Hygiene, Universität Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany
| | | | | | | | | | | |
Collapse
|
24
|
Abstract
The human immunodeficiency virus (HIV) genome encodes a total of three structural proteins, two envelope proteins, three enzymes, and six accessory proteins. Studies over the past ten years have provided high-resolution three-dimensional structural information for all of the viral enzymes, structural proteins and envelope proteins, as well as for three of the accessory proteins. In some cases it has been possible to solve the structures of the intact, native proteins, but in most cases structural data were obtained for isolated protein domains, peptidic fragments, or mutants. Peptide complexes with two regulatory RNA fragments and a protein complex with an RNA recognition/encapsidation element have also been structurally characterized. This article summarizes the high-resolution structural information that is currently available for HIV proteins and reviews current structure-function and structure-biological relationships.
Collapse
Affiliation(s)
- B G Turner
- Howard Hughes Medical Institute, Department of Chemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | | |
Collapse
|
25
|
Tessmer U, Kräusslich HG. Cleavage of human immunodeficiency virus type 1 proteinase from the N-terminally adjacent p6* protein is essential for efficient Gag polyprotein processing and viral infectivity. J Virol 1998; 72:3459-63. [PMID: 9525682 PMCID: PMC109854 DOI: 10.1128/jvi.72.4.3459-3463.1998] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Maturation of infectious human immunodeficiency virus (HIV) particles requires proteolytic cleavage of the structural polyproteins by the viral proteinase (PR), which is itself encoded as part of the Gag-Pol polyprotein. Expression of truncated PR-containing sequences in heterologous systems has mostly led to the autocatalytic release of an 11-kDa species of PR which is capable of processing all known cleavage sites on the viral precursor proteins. Relatively little is known about cleavages within the nascent virus particle, on the other hand, and controversial results concerning the active PR species inside the virion and the relative activities of extended PR species have been reported. Here, we report that HIV type 1 (HIV-1) particles of four different strains obtained from different cell lines contain an 11-kDa PR, with no extended PR proteins detectable. Furthermore, mutation of the N-terminal PR cleavage site leading to production of an N-terminally extended 17-kDa PR species caused a severe defect in Gag polyprotein processing and a complete loss of viral infectivity. We conclude that N-terminal release of PR from the HIV-1 polyprotein is essential for viral replication and suggest that extended versions of PR may have a transient function in the proteolytic cascade.
Collapse
Affiliation(s)
- U Tessmer
- Heinrich-Pette-Institut, Hamburg, Germany
| | | |
Collapse
|
26
|
de Rocquigny H, Petitjean P, Tanchou V, Decimo D, Drouot L, Delaunay T, Darlix JL, Roques BP. The zinc fingers of HIV nucleocapsid protein NCp7 direct interactions with the viral regulatory protein Vpr. J Biol Chem 1997; 272:30753-9. [PMID: 9388214 DOI: 10.1074/jbc.272.49.30753] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The 96-amino acid protein Vpr functions as a regulator of cellular processes involved in human immunodeficiency virus, type 1 (HIV-1) life cycle, in particular by interrupting cells division in the G2 phase. Incorporation of Vpr in the virion was reported to be mediated by the C-terminal domain of the Pr55(Gag) polyprotein precursor, which includes NCp7, a protein involved in the genomic RNA encapsidation and p6, a protein required for particle budding. To precisely define the Gag and Vpr sequences involved in this protein-protein interaction, NCp7, p6, and Vpr as well as a series of derived peptides were synthesized using Fmoc (N-(9-fluorenyl)methoxycarbonyl) chemistry. Binding assays were carried out by Far Western experiments and by competition studies using (52-96)Vpr immobilized onto agarose beads. The results show that interaction between NCp7 and Vpr occurs in vitro by a recognition mechanism requiring the zinc fingers of NCp7 and the last 16 amino acids of Vpr. Moreover, NCp10, the equivalent of NCp7 in Moloney murine leukemia virus but not polysine inhibits Vpr-NCp7 complexation. Interestingly enough, Vpr was found to interact with Gag, NCp15, and NCp7 but not with mature p6 in vitro. In vivo mutations in NCp7 zinc fingers in an HIV-1 molecular clone led to viruses with important defects in Vpr encapsidation. Together, these results suggest that NCp7 cooperates with p6 to induce Vpr encapsidation in HIV-1 mature particles. The NCp7-Vpr complex could also be important for interaction of Vpr with cellular proteins involved in cell division.
Collapse
Affiliation(s)
- H de Rocquigny
- Département de Pharmacochimie Moléculaire et Structurale, INSERM U266, CNRS URA D 1500, UFR des Sciences Pharmaceutiques et Biologiques, 75270 Paris Cedex 06, France
| | | | | | | | | | | | | | | |
Collapse
|