title: CzcR and CzcD, gene products affecting regulation of resistance to cobalt, zinc, and cadmium (czc system) in Alcaligenes eutrophus.
abstract: The czcR gene, one of the two control genes responsible for induction of resistance to Co2+, Zn2+, and Cd2+ (czc system) in the Alcaligenes eutrophus plasmid pMOL30, was cloned and characterized. The 1,376-bp sequence upstream of the czcCBAD structural genes encodes a 41.4-kDa protein, the czcR gene product, transcribed in the opposite direction of that of the czcCBAD genes. The putative CzcR polypeptide (355 amino acid residues) contains 11 cysteine and 14 histidine residues which might form metal cation-binding sites. A czcC::lacZ reporter gene translational fusion was constructed, inserted into plasmid pMOL30 in A. eutrophus, and expressed under the control of CzcR. Zn2+, Co2+, and Cd2+, as well as Ni2+, Cu2+, Hg2+, and Mn2+ and even Al3+, served as inducers of beta-galactosidase activity. Besides the CzcR protein, the membrane-bound CzcD protein was essential for induction of czc. The CzcR and CzcD proteins display no sequence similarity to two-component regulatory systems of a sensor and a response activator type; however, CzcD has 34% identity with the ZRC-1 protein, which mediates zinc resistance in Saccharomyces cerevisiae (A. Kamizomo, M. Nishizawa, Y. Teranishi, K. Murata, and A. Kimura, Mol. Gen. Genet. 219:161-167, 1989).
authors.affiliation: Institut für Pflanzenphysiologie und Mikrobiologie, Freie Universität Berlin, Germany.
authors.forename: D H
authors.initials: DH
authors.lastname: Nies
mesh_terms: D000421:Alcaligenes / Q000235:genetics*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002104:Cadmium / Q000494:pharmacology*; D003001:Cloning, Molecular; D003035:Cobalt / Q000494:pharmacology*; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D015032:Zinc / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D002104:Cadmium; D003035:Cobalt; D015032:Zinc