Identification of the contact surface of a streptococcal protein G domain complexed with a human Fc fragment

J Mol Biol. 1993 Oct 5;233(3):331-5. doi: 10.1006/jmbi.1993.1514.


The B1 domain of streptococcal protein G interacts with the C-terminal fragment of the heavy chain of immunoglobulin G (IgGFc). The binding site for the protein G domain on the antibody fragment is in close proximity or overlapping with that determined for staphylococcal protein A. The interaction of the B1 domain with IgGFc was investigated by 1H-15N correlation spectroscopy. The major interaction site on the B1 domain comprises parts of beta-strand 3 as well as the alpha-helix. Comparison with the crystal structure of the protein A/IgGFc complex suggests that the mode of interaction in the two complexes is analogous, despite the lack of sequence or structural similarity between two antibody binding proteins.

Publication types

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

MeSH terms

  • Bacterial Proteins / chemistry*
  • Humans
  • Immunoglobulin Fc Fragments / chemistry*
  • Immunoglobulin G / chemistry*
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Protein Conformation


  • Bacterial Proteins
  • IgG Fc-binding protein, Streptococcus
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G