title: Structure of the dnaA and DnaA-box region in the Mycoplasma capricolum chromosome: conservation and variations in the course of evolution.
abstract: We have previously shown that the dnaA gene and the DnaA-box region were conserved in bacteria representative of all three major branches of the eubacterial phylogenic tree: high G + C Gram+, low-G + C Gram+ and Gram-. In the present work, we determined the structure of the dnaA region of Mycoplasma capricolum and found that the dnaA gene and at least two other genes, rpmH and dnaN, were conserved in this bacterium. An unusually high level of amino acid (aa) substitutions was observed in M. capricolum DnaA. It was the case even in those aa which were well conserved in other bacterial species. The nontranslatable region upstream from the dnaA gene was also conserved in this bacterium, as it was universally found in both Gram+ and Gram- bacteria. An additional nontranslatable region downstream from the dnaA gene, which is common to Gram+ bacteria, was also found in M. capricolum, consistent with the proposal that M. capricolum is Gram+ in origin. These regions were rich in A + T and contained ten DnaA-box-like sequences (9-mers that differ from TTATCCACA by one or two bases).
authors.affiliation: Department of Pathology, Osaka University Medical School, Japan.
authors.forename: M Q
authors.initials: MQ
authors.lastname: Fujita
authors.forename: H
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: N
authors.initials: N
authors.lastname: Ogasawara
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D005075:Biological Evolution; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D014644:Genetic Variation; D016982:Micrococcus luteus / Q000235:genetics; D008969:Molecular Sequence Data; D009174:Mycoplasma / Q000235:genetics*; D014176:Protein Biosynthesis; D016958:Pseudomonas putida / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria