The structure of E. coli IgG-binding protein D suggests a general model for bending and binding in trimeric autotransporter adhesins

Structure. 2011 Jul 13;19(7):1021-30. doi: 10.1016/j.str.2011.03.021.

Abstract

The Escherichia coli Ig-binding (Eib) proteins are trimeric autotransporter adhesins (TAAs) and receptors for IgG Fc. We present the structure of a large fragment of the passenger domain of EibD, the first TAA structure to have both a YadA-like head domain and the entire coiled-coil stalk. The stalk begins as a right-handed superhelix, but switches handedness halfway down. An unexpected β-minidomain joins the two and inserts a ∼120° rotation such that there is no net twist between the beginning and end of the stalk. This may be important in folding and autotransport. The surprisingly large cavities we found in EibD and other TAAs may explain how TAAs bend to bind their ligands. We identified how IgA and IgG bind and modeled the EibD-IgG Fc complex. We further show that EibD promotes autoagglutination and biofilm formation and forms a fibrillar layer covering the cell surface making zipper-like contacts between cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / chemistry*
  • Adhesins, Bacterial / immunology
  • Adhesins, Bacterial / metabolism
  • Agglutination
  • Amino Acid Sequence
  • Bacterial Adhesion
  • Binding Sites
  • Carrier Proteins / chemistry*
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism
  • Cloning, Molecular
  • Crystallization
  • Crystallography, X-Ray
  • Escherichia coli / chemistry*
  • Escherichia coli / immunology
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / immunology
  • Escherichia coli Proteins / metabolism
  • Immunoglobulin Fc Fragments / chemistry*
  • Immunoglobulin Fc Fragments / immunology
  • Immunoglobulin Fc Fragments / metabolism
  • Immunoglobulin G / chemistry*
  • Immunoglobulin G / immunology
  • Immunoglobulin G / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Plasmids
  • Protein Binding
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Transfection

Substances

  • Adhesins, Bacterial
  • Carrier Proteins
  • Escherichia coli Proteins
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • Recombinant Fusion Proteins

Associated data

  • PDB/2XQH
  • PDB/2XZR