1aqd
From Proteopedia
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'''HLA-DR1 (DRA, DRB1 0101) HUMAN CLASS II HISTOCOMPATIBILITY PROTEIN (EXTRACELLULAR DOMAIN) COMPLEXED WITH ENDOGENOUS PEPTIDE''' | '''HLA-DR1 (DRA, DRB1 0101) HUMAN CLASS II HISTOCOMPATIBILITY PROTEIN (EXTRACELLULAR DOMAIN) COMPLEXED WITH ENDOGENOUS PEPTIDE''' | ||
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[[Category: Murthy, V L.]] | [[Category: Murthy, V L.]] | ||
[[Category: Stern, L J.]] | [[Category: Stern, L J.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 10:34:57 2008'' | |
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Revision as of 07:35, 2 May 2008
HLA-DR1 (DRA, DRB1 0101) HUMAN CLASS II HISTOCOMPATIBILITY PROTEIN (EXTRACELLULAR DOMAIN) COMPLEXED WITH ENDOGENOUS PEPTIDE
Overview
BACKGROUND: Class II major histocompatibility complex (MHC) proteins are cell surface glycoproteins that bind peptides and present them to T cells as part of the mechanism for detecting and responding to foreign material in the body. The peptide-binding activity exhibits allele-specific preferences for particular sidechains at some positions, although the structural basis of these preferences is not understood in detail. We have determined the 2.45 A crystal structure of the human class II MHC protein HLA-DR1 in complex with the tight binding endogenous peptide A2 (103-117) in order to discover peptide-MHC interactions that are important in determining the binding motif and to investigate conformational constraints on the bound peptide. RESULTS: The bound peptide adopts a polyproline II-like conformation and places several sidechains within pockets in the binding site. Bound water molecules mediate MHC-peptide contacts at several sites. A tryptophan residue from the beta 2 'lower' domain of HLA-DR1 was found to project into a pocket underneath the peptide-binding domain and may be important in modulating interdomain interactions in MHC proteins. CONCLUSIONS: The peptide-binding motif of HLA-DR1 includes an aromatic residue at position +1, an arginine residue at position +2, and a small residue at position +6 (where the numbering refers to the normal MHC class II convention); these preferences can be understood in light of interactions observed in the peptide-MHC complex. Comparison of the structure with that of another MHC-peptide complex shows that completely different peptide sequences bind in essentially the same conformation and are accommodated with only minimal rearrangement of HLA-DR1 residues. Small conformational differences that are observed appear to be important in interactions with other proteins.
About this Structure
1AQD is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The class II MHC protein HLA-DR1 in complex with an endogenous peptide: implications for the structural basis of the specificity of peptide binding., Murthy VL, Stern LJ, Structure. 1997 Oct 15;5(10):1385-96. PMID:9351812 Page seeded by OCA on Fri May 2 10:34:57 2008
