Watanabe K, Takasawa T, Yoshimura F, Ozeki M, Kawanami M, Kato H
Department of Periodontology, School of Dentistry, Hokkaido University, Sapporo, Japan.
FEMS Microbiol Lett. 1992 Apr 1;71(1):47-55. doi: 10.1016/0378-1097(92)90540-5.
A major immunodominant surface protein (the 75-kDa protein) of Porphyromonas (Bacteroides) gingivalis 381 has been purified and its amino-terminal amino acid sequence has been determined. Using oligonucleotide probes corresponding to the sequence, we identified a recombinant plasmid clone carrying a single 4.2-kb BamHI fragment from pUC19 libraries of P. gingivalis. The BamHI fragment transferred to the bacteriophage T7 RNA polymerase/promoter expression vector system produced a slightly larger (77-kDa) protein, a precursor form, immunoreactive to the antibody against the 75-kDa protein, suggesting that the cloned DNA fragment probably carried an entire gene for the 75-kDa protein. Genomic Southern analysis revealed a single copy of the 75-kDa protein gene per genome among all P. gingivalis strains tested, and that no homologous genes are present in other black-pigmented Bacteroides species. These observations suggest that the 75-kDa protein gene may be useful as a specific DNA probe to classify or to detect this organism.
