2hmx
From Proteopedia
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HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 MATRIX PROTEIN
Overview
The HIV-1 matrix protein forms an icosahedral shell associated with the, inner membrane of the mature virus. Genetic analyses have indicated that, the protein performs important functions throughout the viral life-cycle, including anchoring the transmembrane envelope protein on the surface of, the virus, assisting in viral penetration, transporting the proviral, integration complex across the nuclear envelope, and localizing the, assembling virion to the cell membrane. We now report the, three-dimensional structure of recombinant HIV-1 matrix protein, determined at high resolution by nuclear magnetic resonance (NMR) methods., The HIV-1 matrix protein is the first retroviral matrix protein to be, characterized structurally and only the fourth HIV-1 protein of known, structure. NMR signal assignments required recently developed, triple-resonance (1H, 13C, 15N) NMR methodologies because signals for 91%, of 132 assigned H alpha protons and 74% of the 129 assignable backbone, amide protons resonate within chemical shift ranges of 0.8 p.p.m. and 1, p.p.m., respectively. A total of 636 nuclear Overhauser effect-derived, distance restraints were employed for distance geometry-based structure, calculations, affording an average of 13.0 NMR-derived distance restraints, per residue for the experimentally constrained amino acids. An ensemble of, 25 refined distance geometry structures with penalties (sum of the squares, of the distance violations) of 0.32 A2 or less and individual distance, violations under 0.06 A was generated; best-fit superposition of ordered, backbone heavy atoms relative to mean atom positions afforded, root-mean-square deviations of 0.50 (+/- 0.08) A. The folded HIV-1 matrix, protein structure is composed of five alpha-helices, a short 3(10) helical, stretch, and a three-strand mixed beta-sheet. Helices I to III and the, 3(10) helix pack about a central helix (IV) to form a compact globular, domain that is capped by the beta-sheet. The C-terminal helix (helix V), projects away from the beta-sheet to expose carboxyl-terminal residues, essential for early steps in the HIV-1 infectious cycle. Basic residues, implicated in membrane binding and nuclear localization functions cluster, about an extruded cationic loop that connects beta-strands 1 and 2. The, structure suggests that both membrane binding and nuclear localization may, be mediated by complex tertiary structures rather than simple linear, determinants.
About this Structure
2HMX is a Single protein structure of sequence from Human immunodeficiency virus 1. This structure superseeds the now removed PDB entry 1HMX. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of the human immunodeficiency virus type 1 matrix protein., Massiah MA, Starich MR, Paschall C, Summers MF, Christensen AM, Sundquist WI, J Mol Biol. 1994 Nov 25;244(2):198-223. PMID:7966331
Page seeded by OCA on Thu Nov 8 14:50:21 2007
