Novel FNR homologues identified in four representative oral facultative anaerobes: Capnocytophaga ochracea, Capnocytophaga sputigena, Haemophilus aphrophilus, and Actinobacillus actinomycetemcomitans.
Based upon DNA sequence data and positive immunochemical reactivity of expressed protein, novel homologues of the FNR family were identified in four representative oral facultative anaerobes: Capnocytophaga ochracea, Capnocytophaga sputigena, Haemophilus aphrophilus, and Actinobacillus actinomycetemcomitans. The similarity to E. coli FNR and to HlyX (itself 71% similar to E. coli FNR, while regulating expression of hemolysin operon in Actinobacillus pleuropneumoniae) was estimated from the deduced partial amino acid sequence to be, in the above order of tested species, 98, 98, 86, and 85%, and 75, 75, 88, and 88%, respectively. The phylogenetic relatedness indicates a rather closer link of HlyX to the FNR homologues from both pathogens, H. aphrophilus and A. actinomycetemcomitans. The possibility that the A. actinomycetemcomitans FNR homologue functions as a redox-sensing transcriptional factor to regulate, in addition to anaerobic respiration, microaerobic expression of the leukotoxin operon (ltx gene) is suggested.
Hattori
T
T
Department of Biochemistry and Molecular Dentistry, Okayama University Dental School, Japan.
Takahashi
K
K
Nakanishi
T
T
Ohta
H
H
Fukui
K
K
Taniguchi
S
S
Takigawa
M
M
D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002206:Capnocytophaga / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005098:Exotoxins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006190:Haemophilus / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007506:Iron-Sulfur Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009055:Mouth / Q000382:microbiology; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D005098:Exotoxins; C060704:FNR protein, E coli; C087924:HlyX protein, Actinobacillus pleuropneumoniae; D007506:Iron-Sulfur Proteins; D014157:Transcription Factors; C018579:leukotoxin