Identification of the cpdA gene encoding cyclic 3',5'-adenosine monophosphate phosphodiesterase in Escherichia coli.
We have identified a gene, cpdA, located at 66.2 min of the chromosome of Escherichia coli that encodes cyclic 3',5'-adenosine monophosphate phosphodiesterase (cAMP phosphodiesterase, EC). The expression of beta-galactosidase, which is a product of the lacZ gene, was repressed in cells that harbored multiple copies of the plasmid carrying the cpdA gene. Northern blotting showed that the transcription of the lacZ gene was inhibited in these cells. Multiple copies of the cpdA gene decreased the intracellular concentration of cAMP, which is a positive regulator for transcription of the lacZ gene. We found that the purified CpdA protein repressed in vitro transcription from the lacP1 promoter by decreasing cAMP. In addition, we showed that the CpdA protein hydrolyzed cAMP to 5'-adenosine monophosphate and that its activity was activated by iron. Our results suggested that regulation of intracellular concentration of cAMP is dependent not only on synthesis of cAMP but also on hydrolysis of cAMP by cAMP phosphodiesterase.
Imamura
R
R
Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto, Kumamoto 862, Japan.
Yamanaka
K
K
Ogura
T
T
Hiraga
S
S
Fujita
N
N
Ishihama
A
A
Niki
H
H
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D017124:Conserved Sequence; D000242:Cyclic AMP / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D005798:Genes, Bacterial; D006639:Histidine; D007700:Kinetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D001616:beta-Galactosidase / Q000096:biosynthesis
D011993:Recombinant Fusion Proteins; D006639:Histidine; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D001616:beta-Galactosidase