2jmg
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(New page: 200px<br /> <applet load="2jmg" size="450" color="white" frame="true" align="right" spinBox="true" caption="2jmg" /> '''Solution structure of V7R mutant of HIV-1 m...)
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Revision as of 12:46, 8 November 2007
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Solution structure of V7R mutant of HIV-1 myristoylated matrix protein
Overview
During the late phase of human immunodeficiency virus type-1 (HIV-1), replication, newly synthesized retroviral Gag proteins are targeted to, lipid raft regions of specific cellular membranes, where they assemble and, bud to form new virus particles. Gag binds preferentially to the plasma, membrane (PM) of most hematopoietic cell types, a process mediated by, interactions between the cellular PM marker, phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P(2)) and Gag's, N-terminally myristoylated matrix (MA) domain. We recently demonstrated, that PI(4,5)P(2) binds to a conserved cleft on MA and promotes myristate, exposure, suggesting a role as both a direct membrane anchor and myristyl, switch trigger. Here we show that PI(4,5)P(2) is also capable of binding, to MA proteins containing point mutations that inhibit membrane binding in, vitro, and in vivo, including V7R, L8A and L8I. However, these mutants do, not exhibit PI(4,5)P(2) or concentration-dependent myristate exposure. NMR, studies of V7R and L8A MA reveal minor structural changes that appear to, be responsible for stabilizing the myristate-sequestered (myr(s)) species, and inhibiting exposure. Unexpectedly, the myristyl group of a revertant, mutant with normal PM targeting properties (V7R,L21K) is also tightly, sequestered and insensitive to PI(4,5)P(2) binding. This mutant binds, PI(4,5)P(2) with twofold higher affinity compared with the native protein, suggesting a potential compensatory mechanism for membrane binding.
About this Structure
2JMG is a Single protein structure of sequence from Human immunodeficiency virus 1 with MYR as ligand. Full crystallographic information is available from OCA.
Reference
Point mutations in the HIV-1 matrix protein turn off the myristyl switch., Saad JS, Loeliger E, Luncsford P, Liriano M, Tai J, Kim A, Miller J, Joshi A, Freed EO, Summers MF, J Mol Biol. 2007 Feb 16;366(2):574-85. Epub 2006 Dec 1. PMID:17188710
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