Rc. Hsia et Pm. Bavoil, SEQUENCE-ANALYSIS OF THE OMP2 REGION OF CHLAMYDIA-PSITTACI STRAIN GPIC - STRUCTURAL AND FUNCTIONAL IMPLICATIONS, Gene, 176(1-2), 1996, pp. 155-162
The nucleotide sequence of a 3.1-kb genomic DNA fragment carrying the
omp3, omp2 and srp gene homologs from Chlamydia psittaci strain GPIC w
as determined. A comparative analysis of the GPIC sequence with other
chlamydial omp2-linked sequences reveals highly conserved omp3 and omp
2 upstream sequences across species, suggesting a unified mechanism of
transcription regulation. In contrast, the omp2-srp intergenic segmen
t, which encompasses hypothetical srp transcriptional initiation sites
, is relatively less conserved in length and in sequence. Examination
of the predicted translation products reveals a high degree of homolog
y within Omp3 and Omp2 across species, with the notable exception of t
he N-terminal fifth of Omp2. Although the latter segment displays rela
tively high interspecies sequence variation, it includes a smaller seg
ment, whose high positive charge density is conserved across species,
suggesting a conserved structure/function. In contrast to Omp2 and Omp
3, a comparative analysis of the predicted amino acid (aa) sequence of
the srp product reveals high homology within species, but relatively
little across species. A 38-aa segment near the C-terminus of Srp, who
se sequence is 64% identical between C. psittaci GPIC and C. trachomat
is, is partially truncated in C. psittaci 6BC.