Disulfide bond that constrains the HIV-1 gp120 V3 domain is cleaved by thioredoxin.

ABSTRACT: A functional disulfide bond in both the HIV envelope glycoprotein, gp120, and its immune cell receptor, CD4, is involved in viral entry, and compounds that block cleavage of the disulfide bond in these proteins inhibit HIV entry and infection. The disulfide bonds in both proteins are cleaved at the cell surface by the small redox protein, thioredoxin. The target gp120 disulfide and its mechanism of cleavage were determined using a thioredoxin kinetic trapping mutant and mass spectrometry. A single disulfide bond was cleaved in isolated and cell surface gp120, but not the gp160 precursor, and the extent of the reaction was enhanced when gp120 was bound to CD4. The Cys(32) sulfur ion of thioredoxin attacks the Cys(296) sulfur ion of the gp120 V3 domain Cys(296)-Cys(331) disulfide bond, cleav

SUBMITTER: Azimi I 

PROVIDER: S-EPMC3000989 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature