Structural reorganization of the antigen-binding groove of human CD1b for presentation of mycobacterial sulfoglycolipids.

ABSTRACT: The mechanisms permitting nonpolymorphic CD1 molecules to present lipid antigens that differ considerably in polar head and aliphatic tails remain elusive. It is also unclear why hydrophobic motifs in the aliphatic tails of some antigens, which presumably embed inside CD1 pockets, contribute to determinants for T-cell recognition. The 1.9-Å crystal structure of an active complex of CD1b and a mycobacterial diacylsulfoglycolipid presented here provides some clues. Upon antigen binding, endogenous spacers of CD1b, which consist of a mixture of diradylglycerols, moved considerably within the lipid-binding groove. Spacer displacement was accompanied by F' pocket closure and an extensive rearrangement of residues exposed to T-cell receptors. Such structural reorganization resulted in reduction

SUBMITTER: Garcia-Alles LF 

PROVIDER: S-EPMC3203780 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature