2H3Z

Structure of the HIV-1 matrix protein bound to di-C4-phosphatidylinositol-(4,5)-bisphosphate

Summary for 2H3Z

• Entry DOI: 10.2210/pdb2h3z/pdb
• Related: 2H3F 2H3I 2H3Q 2H3V
• Descriptor: Gag polyprotein, (2R)-3-{[(R)-HYDROXY{[(1R,2R,3S,4R,5R,6S)-2,3,6-TRIHYDROXY-4,5-BIS(PHOSPHONOOXY)CYCLOHEXYL]OXY}PHOSPHORYL]OXY}PROPANE-1 ,2-DIYL DIBUTANOATE (2 entities in total)
• Functional Keywords: hiv-1 unmyristoylated matrix protein, viral protein
• Biological source: Human immunodeficiency virus 1
• Cellular location: Matrix protein p17: Virion (Potential). Capsid protein p24: Virion (Potential). Nucleocapsid protein p7: Virion (Potential). Reverse transcriptase/ribonuclease H: Virion (Potential). Integrase: Virion (Potential): P12497
• Total number of polymer chains: 1
• Total formula weight: 15368.97

Authors

Saad, J.S.,Miller, J.,Tai, J.,Kim, A.,Ghanam, R.H.,Summers, M.F. (deposition date: 2006-05-23, release date: 2006-07-25, Last modification date: 2024-05-01)

Primary citation

Saad, J.S.,Miller, J.,Tai, J.,Kim, A.,Ghanam, R.H.,Summers, M.F.
Structural basis for targeting HIV-1 Gag proteins to the plasma membrane for virus assembly.
Proc.Natl.Acad.Sci.Usa, 103:11364-11369, 2006

PubMed Abstract: During the late phase of HIV type 1 (HIV-1) replication, newly synthesized retroviral Gag proteins are targeted to the plasma membrane of most hematopoietic cell types, where they colocalize at lipid rafts and assemble into immature virions. Membrane binding is mediated by the matrix (MA) domain of Gag, a 132-residue polypeptide containing an N-terminal myristyl group that can adopt sequestered and exposed conformations. Although exposure is known to promote membrane binding, the mechanism by which Gag is targeted to specific membranes has yet to be established. Recent studies have shown that phosphatidylinositol (PI) 4,5-bisphosphate [PI(4,5)P(2)], a factor that regulates localization of cellular proteins to the plasma membrane, also regulates Gag localization and assembly. Here we show that PI(4,5)P(2) binds directly to HIV-1 MA, inducing a conformational change that triggers myristate exposure. Related phosphatidylinositides PI, PI(3)P, PI(4)P, PI(5)P, and PI(3,5)P(2) do not bind MA with significant affinity or trigger myristate exposure. Structural studies reveal that PI(4,5)P(2) adopts an "extended lipid" conformation, in which the inositol head group and 2'-fatty acid chain bind to a hydrophobic cleft, and the 1'-fatty acid and exposed myristyl group bracket a conserved basic surface patch previously implicated in membrane binding. Our findings indicate that PI(4,5)P(2) acts as both a trigger of the myristyl switch and a membrane anchor and suggest a potential mechanism for targeting Gag to membrane rafts.

PubMed: 16840558
DOI: 10.1073/pnas.0602818103

Experimental method

SOLUTION NMR