GENETIC AND SEROLOGICAL ANALYSIS OF THE IMMUNOGENIC 67-KDA LIPOPROTEIN OF MYCOPLASMA SP. BOVINE GROUP-7

The gene encoding a lipoprotein of 67 kDa, named P67, was cloned from Mycoplasma sp. bovine group 7 strain PG50 and expressed in Escherichia coil K12. Analysis of the amino acid sequence derived from the DNA se quence of the P67 gene revealed a typical prokaryotic signal peptidase II membrane lipoprotein lipid attachment site and a transmembrane str ucture domain in the leader sequence at the amino-terminal end of the protein. Protein P67 showed 91% identical amino acid residues to the l ipoprotein P72 of Mycoplasma mycoides subsp. mycoides small colony typ e (SC) and 53% identical amino acid residues to a peptide of an unassi gned gene on the genome of Mycoplasma capricolum subsp. capricolum. An tibodies made against recombinant P67 reacted with a 67-kDa protein in all Mycoplasma sp. bovine group 7 strains tested and also, to some ex tent, with P72 of Mycoplasma mycoides subsp. mycoides SC, The gene enc oding P67 was present in all strains of Mycoplasma sp. bovine group 7 analysed, but not in other Mycoplasma sp. of the ''mycoides cluster'' and not in the phylogenetically related Mycoplasma putrefaciens. PCR a nd restriction fragment analysis revealed that the gene of P67 is cons erved in all strains of Mycoplasma sp. bovine group 7, A specific PCR reaction based on the P67 gene sequence enabled rapid identification o f strains belonging to Mycoplasma sp. bovine group 7.