Sequence analysis of the gene encoding the major outer membrane protein rOmp B of Rickettsia japonica

Abstract

The complete nucleotide sequence of the gene encoding rOmp B (ompB), one of the two major outer membrane antigen proteins, of Rickettsia japonica was determined and compared to those of the other spotted fever group and typhus group rickettsiae. Open reading frame of the ompB gene of R. japonica consisted of 4,968 nucleotides coding for a putative precursor protein with 1,656 amino acids (aa) in which the N-terminal 1,363 aa and the C-terminal 293 aa encode 135-kilodalton rOmp B and 32-kilodalton β-peptide, respectively. Putative promoter and terminator sequences for transcription were present in the upstream region of the ATG start codon and downstream of the TAA stop codon. Overall sequences of the ompB genes were well conserved beyond the group, especially in the β-peptide regions.