Characterization of the gene for a 30-kilodalton adhesion-related protein of Mycoplasma pneumoniae

A previously identified trypsin-resistant surface protein of Mycoplasma pneumoniae clusters at the tip organelle of virulent mycoplasmas and appears to be essential for cytadherence and virulence. Monoclonal antibodies generated against this protein were used to identify positive recombinant clones from M. pneumoniae genomic DNA libraries. The structural gene was sequenced and contained an open reading frame of 825 nucleotides that encoded a protein of 275 amino acids with a calculated molecular mass of 29,743 Da. This protein (P30) contained three types of repeat sequences at the carboxy end, each consisting of six amino acids. In addition, the protein was proline rich (20.7%) and exhibited significant amino acid homology with the P1 cytadhesin of M. pneumoniae and with several matrix-associated eucaryotic proteins.