Sequence analysis of the omp2 region of Chlamydia psittaci strain GPIC: structural and functional implications.
The nucleotide sequence of a 3.1-kb genomic DNA fragment carrying the omp3, omp2 and srp gene homologs from Chlamydia psittaci strain GPIC was determined. A comparative analysis of the GPIC sequence with other chlamydial omp2-linked sequences reveals highly conserved omp3 and omp2 upstream sequences across species, suggesting a unified mechanism of transcription regulation. In contrast, the omp2-srp intergenic segment, 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 homology within Omp3 and Omp2 across species, with the notable exception of the N-terminal fifth of Omp2. Although the latter segment displays relatively high interspecies sequence variation, it includes a smaller segment, whose high positive charge density is conserved across species, suggesting a conserved structure/function. In contrast to Omp2 and Omp3, 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, whose sequence is 64% identical between C. psittaci GPIC and C. trachomatis, is partially truncated in C. psittaci 6BC.
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Department of Microbiology and Immunology, University of Rochester Medical Center, NY 14642, USA.
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D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002691:Chlamydophila psittaci / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; C063931:Omp2 protein, bacteria