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The crystal structure of H-2D(b) complexed with a partial peptide epitope suggests a major histocompatibility complex

Ann Glithero1, Jose Tormo, Klaus Doering

  • 1Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 4RU, United Kingdom.

The Journal of Biological Chemistry
|February 16, 2006
PubMed

Insights

Major histocompatibility complex (MHC) class I molecules require peptides for stability. Researchers found a short pentapeptide can stabilize H-2D(b) molecules, revealing minimal requirements for MHC class I folding.

Area of Science:

  • Immunology
  • Structural Biology
  • Biochemistry

Background:

  • Major histocompatibility complex (MHC) class I molecules are crucial for immune responses.
  • MHC class I molecules are unstable without bound peptide ligands, necessitating peptide binding for proper folding and stability.

Purpose of the Study:

  • To determine the minimum peptide requirement for stabilizing MHC class I molecules.
  • To investigate the in vitro folding of H-2D(b) using short synthetic peptides.

Main Methods:

  • Utilized short synthetic peptides derived from the Sendai virus nucleoprotein epitope.
  • Employed in vitro folding assays with H-2D(b) molecules.
  • Crystallized the complex of H-2D(b) with a stabilizing pentapeptide for structural determination.

Main Results:

  • Identified the pentapeptide 5NYPAL9 as sufficient to stabilize H-2D(b).
  • The pentapeptide represents the C-terminal portion of an optimal nonapeptide and contains key anchor residues (P5 and P9).
  • Structural analysis revealed how a single binding pocket occupancy by the pentamer can form a quasi-stable MHC class I molecule.

Conclusions:

  • Minimal peptide fragments, including essential anchor residues, can stabilize MHC class I molecules.
  • This finding provides insights into the structural basis of peptide-MHC class I interactions and stability.
  • The study elucidates the minimum requirements for peptide-dependent MHC class I folding and stabilization.

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