Sequence analysis of the gene encoding a spotted fever group-specific intracytoplasmic protein PS120 of Rickettsia japonica

The 3,438-nucleotide (nt) sequence containing a 3,054-nt open reading frame of the gene (rps120) encoding an antigenic, intracytoplasmic, spotted fever group-specific and heat-stable 120-kilodalton protein (PS120) of Rickettsia japonica was determined. The nt and deduced 1,018 amino-acid (aa) sequences were compared to those of R. conorii since only those of this species had been determined among SFG rickettsiae. The homologies of these sequences between R. japonica and R. conorii were considerably high at 97 and 95%, respectively. These high homologies were comparable to those of beta-peptides encoded by the ompB genes among SFG rickettsiae. It was also found that the genome of R. prowazekii contained a nt sequence with 68% homology to that of the rps120 gene of R. japonica.