The three-dimensional structure of HLA-B27 at 2.1 A resolution suggests a general mechanism for tight peptide binding to MHC

Cell. 1992 Sep 18;70(6):1035-48. doi: 10.1016/0092-8674(92)90252-8.


Cell surface complexes of class I MHC molecules and bound peptide antigens serve as specific recognition elements controlling the cytotoxic immune response. The 2.1 A structure of the human class I MHC molecule HLA-B27 provides a detailed composite image of a co-crystallized collection of HLA-B27-bound peptides, indicating that they share a common main-chain structure and length. It also permits direct visualization of the conservation of arginine as an "anchor" side chain at the second peptide position, which is bound in a potentially HLA-B27-specific pocket and may therefore have a role in the association of HLA-B27 with several diseases. Tight peptide binding to class I MHC molecules appears to result from the extensive contacts found at the ends of the cleft between peptide main-chain atoms and conserved MHC side chains, which also involve the peptide in stabilizing the three-dimensional fold of HLA-B27. The concentration of binding interactions at the peptide termini permits extensive sequence (and probably some length) variability in the center of the peptide, where it is exposed for T cell recognition.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Arginine / metabolism
  • HLA-B27 Antigen / chemistry*
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Structure-Activity Relationship
  • X-Ray Diffraction


  • HLA-B27 Antigen
  • Arginine