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Basic Characteristics of Mutations
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Mutation Site
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L8I |
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Mutation Site Sentence
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Subsequent NMR studies revealed that point mutations in the N-terminal region of MA (e.g., V7R, L8A, or L8I) that impaired membrane targeting of Gag and inhibited virus assembly and release did not exhibit concentration-dependent myristate exposure. Structural data revealed conformational changes that appeared to be responsible for stabilizing the myristate-sequestered species and inhibiting exposure. |
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Mutation Level
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Amino acid level |
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Mutation Type
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nonsynonymous substitution |
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Gene/Protein/Region
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MA |
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Standardized Encoding Gene
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Gag
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Genotype/Subtype
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HIV-1 |
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Viral Reference
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-
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Functional Impact and Mechanisms
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Disease
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HIV Infections
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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- |
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Treatment
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- |
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Location
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- |
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Literature Information
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PMID
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33485964
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Title
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Structural characterization of HIV-1 matrix mutants implicated in envelope incorporation
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Author
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Eastep GN,Ghanam RH,Green TJ,Saad JS
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Journal
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The Journal of biological chemistry
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Journal Info
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2021 Jan-Jun;296:100321
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Abstract
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During the late phase of HIV-1 infection, viral Gag polyproteins are targeted to the plasma membrane (PM) for assembly. Gag localization at the PM is a prerequisite for the incorporation of the envelope protein (Env) into budding particles. Gag assembly and Env incorporation are mediated by the N-terminal myristoylated matrix (MA) domain of Gag. Nonconservative mutations in the trimer interface of MA (A45E, T70R, and L75G) were found to impair Env incorporation and infectivity, leading to the hypothesis that MA trimerization is an obligatory step for Env incorporation. Conversely, Env incorporation can be rescued by a compensatory mutation in the MA trimer interface (Q63R). The impact of these MA mutations on the structure and trimerization properties of MA is not known. In this study, we employed NMR spectroscopy, X-ray crystallography, and sedimentation techniques to characterize the structure and trimerization properties of HIV-1 MA A45E, Q63R, T70R, and L75G mutant proteins. NMR data revealed that these point mutations did not alter the overall structure and folding of MA but caused minor structural perturbations in the trimer interface. Analytical ultracentrifugation data indicated that mutations had a minimal effect on the MA monomer-trimer equilibrium. The high-resolution X-ray structure of the unmyristoylated MA Q63R protein revealed hydrogen bonding between the side chains of adjacent Arg-63 and Ser-67 on neighboring MA molecules, providing the first structural evidence for an additional intermolecular interaction in the trimer interface. These findings advance our knowledge of the interplay of MA trimerization and Env incorporation into HIV-1 particles.
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Sequence Data
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-
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