1SJH

HLA-DR1 complexed with a 13 residue HIV capsid peptide

Summary for 1SJH

• Entry DOI: 10.2210/pdb1sjh/pdb
• Related: 1KLU 1PYW 1SJE
• Descriptor: HLA class II histocompatibility antigen, DR alpha chain, HLA class II histocompatibility antigen, DRB1-1 beta chain, GAG polyprotein, ... (5 entities in total)
• Functional Keywords: mhc class ii, major histocompatibility protein complex, hla-dr1, hiv-1, capsid, superantigen, antigen, gag, immune system
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 72091.87

Authors

Zavala-Ruiz, Z.,Strug, I.,Walker, B.D.,Norris, P.J.,Stern, L.J. (deposition date: 2004-03-03, release date: 2004-08-17, Last modification date: 2023-08-23)

Primary citation

Zavala-Ruiz, Z.,Strug, I.,Walker, B.D.,Norris, P.J.,Stern, L.J.
A hairpin turn in a class II MHC-bound peptide orients residues outside the binding groove for T cell recognition.
Proc.Natl.Acad.Sci.Usa, 101:13279-13284, 2004

PubMed Abstract: T cells generally recognize peptide antigens bound to MHC proteins through contacts with residues found within or immediately flanking the seven- to nine-residue sequence accommodated in the MHC peptide-binding groove. However, some T cells require peptide residues outside this region for activation, the structural basis for which is unknown. Here, we have investigated a HIV Gag-specific T cell clone that requires an unusually long peptide antigen for activation. The crystal structure of a minimally antigenic 16-mer bound to HLA-DR1 shows that the peptide C-terminal region bends sharply into a hairpin turn as it exits the binding site, orienting peptide residues outside the MHC-binding region in position to interact with a T cell receptor. Peptide truncation and substitution studies show that both the hairpin turn and the extreme C-terminal residues are required for T cell activation. These results demonstrate a previously unrecognized mode of MHC-peptide-T cell receptor interaction.

PubMed: 15331779
DOI: 10.1073/pnas.0403371101

Experimental method

X-RAY DIFFRACTION (2.25 Å)