Malarial EBA-175 region VI crystallographic structure reveals a KIX-like binding interface

J Mol Biol. 2008 Jan 18;375(3):773-81. doi: 10.1016/j.jmb.2007.10.071. Epub 2007 Nov 1.

Abstract

The malaria parasite proliferates in the bloodstream of its vertebrate host by invading and replicating within erythrocytes. To achieve successful invasion, a number of discrete and essential events need to take place at the parasite-host cell interface. Erythrocyte-binding antigen 175 (EBA-175) is a member of a family of Plasmodium falciparum erythrocyte-binding proteins involved in the formation of a tight junction, a necessary step in invasion. Here we present the crystal structure of EBA-175 region VI (rVI), a cysteine-rich domain that is highly conserved within the protein family and is essential for EBA-175 trafficking. The structure was solved by selenomethionine single-wavelength anomalous dispersion at 1.8 A resolution. It reveals a homodimer, containing in each subunit a compact five-alpha-helix core that is stabilized by four conserved disulfide bridges. rVI adopts a novel fold that is likely conserved across the protein family, indicating a conserved function. It shows no similarity to the Duffy-binding-like domains of EBA-175 involved in erythrocyte binding, indicating a distinct role. Remarkably, rVI possesses structural features related to the KIX-binding domain of the coactivator CREB-binding protein, supporting the binding and trafficking roles that have been ascribed to it and providing a rational basis for further experimental investigation of its function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, Protozoan*
  • Binding Sites
  • Crystallography, X-Ray
  • Cysteine / chemistry
  • Dimerization
  • Disulfides / chemistry
  • Duffy Blood-Group System / chemistry
  • Duffy Blood-Group System / metabolism*
  • Erythrocytes / metabolism*
  • Humans
  • Hydrogen-Ion Concentration
  • Hydrophobic and Hydrophilic Interactions
  • Malaria / blood*
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Weight
  • Plasmodium falciparum / chemistry*
  • Plasmodium falciparum / metabolism*
  • Plasmodium falciparum / pathogenicity
  • Protein Binding
  • Protein Folding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Protozoan Proteins / blood*
  • Sequence Homology, Amino Acid
  • Water / chemistry

Substances

  • Antigens, Protozoan
  • Disulfides
  • Duffy Blood-Group System
  • Protozoan Proteins
  • Water
  • Cysteine

Associated data

  • PDB/2RJI