PMID:7721706

Citation	Shelver, D, Kerby, RL, He, Y and Roberts, GP (1995) Carbon monoxide-induced activation of gene expression in Rhodospirillum rubrum requires the product of cooA, a member of the cyclic AMP receptor protein family of transcriptional regulators. J. Bacteriol. 177:2157-63
Abstract	Induction of the CO-oxidizing system of the photosynthetic bacterium Rhodospirillum rubrum is regulated at the level of gene expression by the presence of CO. In this paper, we describe the identification of a gene that is required for CO-induced gene expression. An 11-kb deletion of the region adjacent to the previously characterized cooFSCTJ region resulted in a mutant unable to synthesize CO dehydrogenase in response to CO and unable to grow utilizing CO as an energy source. A 2.5-kb region that corresponded to a portion of the deleted region complemented this mutant for its CO regulation defect, restoring its ability to grow utilizing CO as an energy source. When the 2.5-kb region was sequenced, one open reading frame, designated cooA, predicted a product showing similarity to members of the cyclic AMP receptor protein (CRP) family of transcriptional regulators. The product, CooA, is 28% identical (51% similar) to CRP and 18% identical (45% similar) to FNR from Escherichia coli. The insertion of a drug resistance cassette into cooA resulted in a mutant that could not grow utilizing CO as an energy source. CooA contains a number of cysteine residues substituted at, or adjacent to, positions that correspond to residues that contact cyclic AMP in the crystal structure of CRP. A model based on this observation is proposed for the recognition of CO by Cooa. Adjacent to cooA are two genes, nadB and nadC, with predicted products similar to proteins in other bacteria that catalyze reactions in the de novo synthesis of NAD.(ABSTRACT TRUNCATED AT 250 WORDS)
Links	PubMed PMC176861
Keywords	Amino Acid Sequence; Bacterial Proteins/genetics; Carbon Monoxide/pharmacology; Carrier Proteins; Cyclic AMP Receptor Protein/genetics; Escherichia coli/genetics; Escherichia coli Proteins; Gene Expression Regulation, Bacterial/drug effects; Genes, Bacterial; Hemeproteins/genetics; Iron-Sulfur Proteins; Molecular Sequence Data; Mutagenesis, Insertional; Niacin/pharmacology; Rhodospirillum rubrum/drug effects; Rhodospirillum rubrum/genetics; Rhodospirillum rubrum/metabolism; Sequence Deletion; Sequence Homology, Amino Acid; Trans-Activators/genetics; Transcription, Genetic
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RHORU:COOS		GO:0018492: carbon-monoxide dehydrogenase (acceptor) activity	ECO:0000314:		F		Figure 3	complete CACAO 3453
RHORU:NADB		GO:0009435: NAD biosynthetic process	ECO:0000315:		P		"In the course of this study, we also identified the R. rubrum nadBC genes. This conclusion is based on their very strong sequence similarity to nadBC in E. coli (18, 20) and on the Nic2 phenotype caused by their deletion from the R. rubrum chromosome. In contrast to the homologous genes of E. coli, which map to different regions of the chromosome (19), the nadB and nadC genes of R. rubrum appear to form an operon. In R. rubrum, the juxtaposition of the coo and nad genes appears to be coincidental, as no physiological connection between the two has been established: the nad deletion confers a Nic2 phenotype in the absence of coo expression, and the insertion in cooA causes no apparent Nic 2 phenotype in a nad1 background."	complete CACAO 3283
RHORU:NADB	involved_in	GO:0009435: NAD biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
RHORU:NADC		GO:0009435: NAD biosynthetic process	ECO:0000315:		P		Deletion of nadBC results in a nicotinic acid auxotroph.	complete CACAO 3290
RHORU:NADC	involved_in	GO:0009435: NAD biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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