Analysis of a collagen-binding trimeric autotransporter adhesin from Mannheimia haemolytica A1.
A locus that codes for a high-molecular-weight adhesin was previously isolated from Mannheimia haemolytica A1. In this study, we showed that this locus, named ahs, codes for two proteins (AhsA and AhsB) that exhibit characteristics of a trimeric autotransporter adhesin. Sequence analysis of AhsA showed the presence of 21 collagen-binding motifs in the protein. Collagen-binding assays showed that M. haemolytica A1 binds to collagen in a dose-dependent manner. This binding activity is trypsin sensitive and can be inhibited by anti-AhsA antibody. AhsB is the cognate transporter for AhsA. The C-terminal of AhsB showed highly conserved amino acids typical of trimeric autotransporters. Experimental data showed that the C-terminal 120 amino acids of AhsB could indeed form trimeric molecules. Western immunoblots showed the presence of anti-AhsA antibodies in the sera of calves that had been challenged with M. haemolytica A1, suggesting that AhsA is expressed and immunogenic in cattle.
Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
Michelle C
MC
Daigneault
Reggie Y C
RY
Lo
D018829:Adhesins, Bacterial / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001665:Binding Sites; D002417:Cattle; D003094:Collagen / Q000378:metabolism*; D017124:Conserved Sequence; D016978:Mannheimia haemolytica / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D016871:Pasteurellaceae Infections / Q000276:immunology / Q000662:veterinary; D011485:Protein Binding; D055503:Protein Multimerization; D017422:Sequence Analysis, DNA
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D026901:Membrane Transport Proteins; D003094:Collagen