ANALYSIS OF TANDEM, MULTIPLE GENES ENCODING 30-KDA MEMBRANE-PROTEINS IN PASTEURELLA-HAEMOLYTICA A1

A number of outer membrane proteins (OMPs), including a 30-kDa protein , may be important in eliciting immunity to Pasteurella haemolytica A1 , the causative agent of bovine pneumonic pasteurellosis. To better un derstand the nature of the 30-kDa antigen, several genes encoding this protein were sequenced. Sequence analysis revealed that three separat e genes encoding similar, yet distinct, versions of the 30-kDa protein are tandemly arranged on the P. haemolytica A1 chromosome. The genes appear to be transcribed from a single promoter. The deduced amino aci d sequences of the proteins encoded by these genes are similar to a 28 -kDa inner membrane lipoprotein of Escherichia coli and a 28-kDa membr ane protein which may contribute to the virulence of Haemophilus influ enzae type b strains.