1xz0
From Proteopedia
Crystal structure of CD1a in complex with a synthetic mycobactin lipopeptide
Contents |
Overview
CD1a is expressed on Langerhans cells (LCs) and dendritic cells (DCs), where it mediates T cell recognition of glycolipid and lipopeptide antigens that contain either one or two alkyl chains. We demonstrate here that CD1a-restricted T cells can discriminate the peptide component of didehydroxymycobactin lipopeptides. Structure analysis of CD1a cocrystallized with a synthetic mycobactin lipopeptide at 2.8 A resolution further reveals that the single alkyl chain is inserted deep within the A' pocket of the groove, whereas its two peptidic branches protrude along the F' pocket to the outer, alpha-helical surface of CD1a for recognition by the TCR. Remarkably, the cyclized lysine branch of the peptide moiety lies in the shallow F' pocket in a conformation that closely mimics that of the alkyl chain in the CD1a-sulfatide structure. Thus, this structural study illustrates how a single chain lipid can be presented by CD1 and that the peptide moiety of the lipopeptide is recognized by the TCR.
Disease
Known disease associated with this structure: Hypoproteinemia, hypercatabolic OMIM:[109700]
About this Structure
1XZ0 is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Molecular mechanism of lipopeptide presentation by CD1a., Zajonc DM, Crispin MD, Bowden TA, Young DC, Cheng TY, Hu J, Costello CE, Rudd PM, Dwek RA, Miller MJ, Brenner MB, Moody DB, Wilson IA, Immunity. 2005 Feb;22(2):209-19. PMID:15723809 Page seeded by OCA on Sat May 3 15:41:04 2008
