Qa-1b binds conserved class I leader peptides derived from several mammalian species

Zoran Kurepa, Charles A. Hasemann, James Forman

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Qa-1b binds a peptide (AMAPR TLLL), referred to as Qdm (for Qa-1 determinant modifier), derived from the signal sequence of murine class Ia molecules. This peptide binds with high affinity and accounts for almost all of the peptides associated with this molecule. Human histocompatibility leukocyte antigen (HLA)-E, a homologue of Qa-1b, binds similar peptides derived from human class Ia molecules and interacts with CD94/NKG2 receptors on natural killer cells. We used surface plasmon resonance to determine the ability of Qa-1b to bind related ligands representing peptides derived from the leaders of class I molecules from several mammalian species. All of the peptides reported to bind HLA-E bound readily to Qa-1b. In addition, peptides derived from leader segments of different mammals also bound to Qa- 1b, indicating a conservation of this 'Qdm-like' epitope throughout mammalian evolution. We have attempted to define a minimal peptide on a polyglycine backbone that binds Qa-1b. Our previous findings showed that P2 and P9 are important but not sufficient for binding to Qa-1b. Although a minimum peptide (GMGGGGLLL) bound Qa-1b, its interaction was relatively weak, as were peptides sharing five or six residues with Qdm, indicating that multiple native residues are required for a strong interaction. This finding is consistent with the observation that this molecule preferentially binds this single ligand.

Original languageEnglish (US)
Pages (from-to)973-978
Number of pages6
JournalJournal of Experimental Medicine
Issue number5
StatePublished - Sep 7 1998


  • Binding
  • Major histocompatibility complex class Ib
  • Peptide
  • Qa-1
  • Surface plasmon resonance

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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