1l6n
STRUCTURE OF THE N-TERMINAL 283-RESIDUE FRAGMENT OF THE HIV-1 GAG POLYPROTEIN
OverviewOverview
The capsid protein (CA) of the mature human immunodeficiency virus (HIV) contains an N-terminal beta-hairpin that is essential for formation of the capsid core particle. CA is generated by proteolytic cleavage of the Gag precursor polyprotein during viral maturation. We have determined the NMR structure of a 283-residue N-terminal fragment of immature HIV-1 Gag (Gag(283)), which includes the intact matrix (MA) and N-terminal capsid (CA(N)) domains. The beta-hairpin is unfolded in Gag(283), consistent with the proposal that hairpin formation occurs subsequent to proteolytic cleavage of Gag, triggering capsid assembly. Comparison of the immature and mature CA(N) structures reveals that beta-hairpin formation induces a approximately 2 A displacement of helix 6 and a concomitant displacement of the cyclophylin-A (CypA)-binding loop, suggesting a possible allosteric mechanism for CypA-mediated destabilization of the capsid particle during infectivity.
About this StructureAbout this Structure
1L6N is a Single protein structure of sequence from Human immunodeficiency virus 1. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the N-terminal 283-residue fragment of the immature HIV-1 Gag polyprotein., Tang C, Ndassa Y, Summers MF, Nat Struct Biol. 2002 Jul;9(7):537-43. PMID:12032547 Page seeded by OCA on Fri May 2 23:35:51 2008