A DNA fragment has been isolated from the genome of Mycoplasma pirum b
y use of a genetic probe derived from the conserved region within the
genes for the major adhesins of Mycoplasma genitalium and Mycoplasma p
neumoniae. A gene encoding an adhesin-like polypeptide was localized,
and sequence analysis indicated a G+C content of only 28%, with A- and
T-rich codons being preferentially used. A total of 91% of positions
3 were either A or T. The deduced polypeptide is 1,144 amino acids lon
g (126 kDa) and shows 26% identity with the adhesins of M. genitalium
and M. pneumoniae. Other features in common with these two membrane pr
oteins include a similar hydropathic profile and a proline-rich C term
inus. Antibodies were prepared by using as an immunogen a peptide deri
ved from the C terminus of the M. pirum adhesin-like polypeptide and w
ere found to recognize on immunoblots a 126-kDa polypeptide from an M.
pirum cellular extract. The characterization of the adhesin-like gene
is a first step toward a better understanding of the mechanisms allow
ing this human mycoplasma to attach to host cells.