Related Experiment Video
Updated: Jun 6, 2026

Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
Published on: October 2, 2017
A structural basis for Staphylococcal complement subversion: X-ray structure of the complement-binding domain of
Elizabeth A Clark1, Susan Crennell, Abhishek Upadhyay
1University of Bath, Department of Biology and Biochemistry, Claverton Down, Bath BA2 7AY, United Kingdom.
Abstract:
The structure of the complement-binding domain of Staphylococcus aureus protein Sbi (Sbi-IV) in complex with ligand C3d is presented. The 1.7Å resolution structure reveals the molecular details of the recognition of thioester-containing fragment C3d of the central complement component C3, involving interactions between residues of Sbi-IV helix α2 and the acidic concave surface of C3d. The complex provides a structural basis for the binding preference of Sbi for native C3 over C3b and explains how Sbi-IV inhibits the interaction between C3d and complement receptor 2. A second C3d binding site on Sbi-IV is identified in the crystal structure that is not observed in related S. aureus C3 inhibitors Efb-C and Ehp. This binding mode perhaps hints as to how Sbi-IV, as part of Sbi, forms a C3b-Sbi adduct and causes futile consumption of C3, an extraordinary aspect of Sbi function that is not shared by any other known Staphylococcal complement inhibitor.
Related Concept Videos
Complement System
Staphylococcal Skin Infections
Mechanism of Antibiotic Resistance in MRSA
Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
Determinants of Bacterial Pathogenicity and Virulence
Clinical Significance of Antibiotic Resistance

