Conformation and dynamics of the Gag polyprotein of the human immunodeficiency virus 1 studied by NMR spectroscopy.

ABSTRACT: Assembly and maturation of the human immunodeficiency virus type 1 (HIV-1) are governed by the Gag polyprotein. Here we study the conformation and dynamics of a large HIV-1 Gag fragment comprising the matrix, capsid, spacer peptide 1 and nucleocapsid domains (referred to as ?Gag) by heteronuclear multidimensional NMR spectroscopy. In solution, ?Gag exists in a dynamic equilibrium between monomeric and dimeric states. In the presence of nucleic acids and at low ionic strength ?Gag assembles into immature virus-like particles. The structured domains of ?Gag (matrix, the N- and C-terminal domains of capsid, and the N- and C-terminal zinc knuckles of nucleocapsid) retain their fold and reorient semi-independently of one another; the linkers connecting the structural domains, including spacer peptide 1 that connects capsid to nucleocapsid, are intrinsically disordered. Structural changes in ?Gag upon proteolytic processing by HIV-1 protease, monitored by NMR in real-time, demonstrate that the conformational transition of the N-terminal 13 residues of capsid from an intrinsically disordered coil to a ?-hairpin upon cleavage at the matrix|capsid junction occurs five times faster than cleavage at the capsid|spacer peptide 1 junction. Finally, nucleic acids interact with both nucleocapsid and matrix domains, and proteolytic processing at the spacer peptide 1|nucleocapsid junction by HIV-1 protease is accelerated in the presence of single-stranded DNA.

SUBMITTER: Deshmukh L 

PROVIDER: S-EPMC4371905 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature