CLONING AND EXPRESSION OF P60, A CONSERVED SURFACE-LOCALIZED PROTEIN OF MYCOPLASMA-HOMINIS, IN ESCHERICHIA-COLI

The clp60 gene encoding P60, a conserved lipoprotein of Mycoplasma hom inis, was cloned and sequenced from both the type strain PG21 and the isolate FBG, Both open reading frames were identical in length, compri sing 1746 nucleotides. The deduced amino acid sequences differed in 16 out of 582 amino acids, As expected, none of these divergences mapped within the epitope that was recognized by mAb CG4 in all of the 198 i solates of M. hominis analyzed so far. This conserved epitope was narr owed down to amino acids 454 through 464 within the C terminus of P60. For the expression of the recombinant homolog P60, p60(rec), in E. co li the TGA codons of clp60 were substituted for TGG codons prior to cl oning of clp60 into the expression plasmid pQE41,The expression of p60 (rec) as a fusion protein with dihydrofolate reductase carrying an N-t erminal His-tag enabled the purification of large amounts of P60(rec) in a soluble form.