1I5Y: Hiv-1 Gp41 Core

Membrane fusion by human immunodeficiency virus type 1 (HIV-1) is promoted by the refolding of the viral envelope glycoprotein into a fusion-active conformation. The structure of the gp41 ectodomain core in its fusion-active state is a trimer of hairpins in which three antiparallel carboxyl-terminal helices pack into hydrophobic grooves on the surface of an amino-terminal trimeric coiled coil. In an effort to identify amino acid residues in these grooves that are critical for gp41 activation, we have used alanine-scanning mutagenesis to investigate the importance of individual side chains in determining the biophysical properties of the gp41 core and the membrane fusion activity of the gp120-gp41 complex. Alanine substitutions at Leu-556, Leu-565, Val-570, Gly-572, and Arg-579 positions severely impaired membrane fusion activity in envelope glycoproteins that were for the most part normally expressed. Whereas alanine mutations at Leu-565 and Val-570 destabilized the trimer-of-hairpins structure, mutations at Gly-572 and Arg-579 led to the formation of a stable gp41 core. Our results suggest that the Leu-565 and Val-570 residues are important determinants of conserved packing interactions between the amino- and carboxyl-terminal helices of gp41. We propose that the high degree of sequence conservation at Gly-572 and Arg-579 may result from selective pressures imposed by prefusogenic conformations of the HIV-1 envelope glycoprotein. Further analysis of the gp41 activation process may elucidate targets for antiviral intervention.
PDB ID: 1I5YDownload
MMDB ID: 20573
PDB Deposition Date: 2001/3/1
Updated in MMDB: 2011/11
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 1I5Y: trimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1I5Y
Label Count Molecule
Proteins (3 molecules)
Transmembrane Glycoprotein (Gp41)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB