Fibronectin binding to the Salmonella enterica serotype Typhimurium ShdA autotransporter protein is inhibited by a monoclonal antibody recognizing the A3 repeat.
ShdA is a large outer membrane protein of the autotransporter family whose passenger domain binds the extracellular matrix proteins fibronectin and collagen I, possibly by mimicking the host ligand heparin. The ShdA passenger domain consists of approximately 1,500 amino acid residues that can be divided into two regions based on features of the primary amino acid sequence: an N-terminal nonrepeat region followed by a repeat region composed of two types of imperfect direct amino acid repeats, called type A and type B. The repeat region bound bovine fibronectin with an affinity similar to that for the complete ShdA passenger domain, while the nonrepeat region exhibited comparatively low fibronectin-binding activity. A number of fusion proteins containing truncated fragments of the repeat region did not bind bovine fibronectin. However, binding of the passenger domain to fibronectin was inhibited in the presence of immune serum raised to one truncated fragment of the repeat region that contained repeats A2, B8, A3, and B9. Furthermore, a monoclonal antibody that specifically recognized an epitope in a recombinant protein containing the A3 repeat inhibited binding of ShdA to fibronectin.
Kingsley
Robert A
RA
Department of Medical Microbiology and Immunology, College of Medicine, College Station, TX 77843, USA. rak@sanger.ac.uk
Abi Ghanem
Daad
D
Puebla-Osorio
Nahum
N
Keestra
A Marijke
AM
Berghman
Luc
L
Bäumler
Andreas J
AJ
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D001665:Binding Sites; D018604:Epitope Mapping; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism*; D007106:Immune Sera / Q000276:immunology / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012486:Salmonella typhimurium / Q000378:metabolism / Q000472:pathogenicity*
D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D005353:Fibronectins; D007106:Immune Sera; D011993:Recombinant Fusion Proteins; C409034:ShdA protein, Salmonella enterica