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.
Daigneault
Michelle C
MC
Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
Lo
Reggie Y C
RY
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