Structures of HLA-A*1101 complexed with immunodominant nonamer and decamer HIV-1 epitopes clearly reveal the presence of a middle, secondary anchor residue

J Immunol. 2004 May 15;172(10):6175-84. doi: 10.4049/jimmunol.172.10.6175.

Abstract

HLA-A*1101 is one of the most common human class I alleles worldwide. An increased frequency of HLA-A*1101 has been observed in cohorts of female sex workers from Northern Thailand who are highly exposed to HIV-1 and yet have remained persistently seronegative. In view of this apparent association of HLA-A*1101 with resistance to acquisition of HIV-1 infection, and given the importance of eliciting strong CTL responses to control and eliminate HIV-1, we have determined the crystal structure of HLA-A*1101 complexed with two immunodominant HIV-1 CTL epitopes: the nonamer reverse transcriptase(313-321) (AIFQSSMTK) and decamer Nef(73-82) (QVPLRPMTYK) peptides. The structures confirm the presence of primary anchor residues P2-Ile/-Val and P9-/P10-Lys, and also clearly reveal the presence of secondary anchor residues P6-Ser for reverse transcriptase and P7-Met for Nef. The overall backbone conformation of both peptides is defined as two bulges that are separated by a more buried middle residue. In this study, we discuss how this topology may offer functional advantages in the selection and presentation of HIV-1 CTL epitopes by HLA-A*1101. Overall, this structural analysis permits a more accurate definition of the peptide-binding motif of HLA-A*1101, the characterization of its antigenic surface, and the correlation of molecular determinants with resistance to HIV-1 infection. These studies are relevant for the rational design of HLA-A*1101-restricted CTL epitopes with improved binding and immunological properties for the development of HIV-1 vaccines.

Publication types

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

MeSH terms

  • Alleles
  • Crystallography, X-Ray
  • Epitopes, T-Lymphocyte / chemistry*
  • Epitopes, T-Lymphocyte / metabolism
  • Female
  • Gene Products, nef / chemistry
  • Gene Products, nef / metabolism
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / metabolism
  • HIV-1 / immunology*
  • HLA-A Antigens / chemistry*
  • HLA-A11 Antigen
  • Humans
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Immunodominant Epitopes / chemistry*
  • Immunodominant Epitopes / metabolism
  • Peptide Fragments / chemistry*
  • Peptide Fragments / immunology
  • Peptide Fragments / metabolism
  • Protein Binding / immunology
  • Protein Conformation
  • Receptors, Antigen, T-Cell / chemistry
  • Receptors, Antigen, T-Cell / metabolism
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / metabolism
  • Thermodynamics
  • nef Gene Products, Human Immunodeficiency Virus

Substances

  • Epitopes, T-Lymphocyte
  • Gene Products, nef
  • HLA-A Antigens
  • HLA-A11 Antigen
  • Immunodominant Epitopes
  • Peptide Fragments
  • Receptors, Antigen, T-Cell
  • nef Gene Products, Human Immunodeficiency Virus
  • HIV Reverse Transcriptase

Associated data

  • PDB/1Q94
  • PDB/1QVO