This is a family of metal-sensitive repressors, involved in resistance to metal ions. Members of this family bind copper, nickel or cobalt ions via conserved cysteine and histidine residues. In the absence of metal ions, these proteins bind to promoter regions and repress transcription. When bound to metal ions they are unable to bind DNA, leading to transcriptional derepression [1-5].

1: CsoR is a novel Mycobacterium tuberculosis copper-sensing transcriptional regulator. Liu T, Ramesh A, Ma Z, Ward SK, Zhang L, George GN, Talaat AM, Sacchettini JC, Giedroc DP; Nat Chem Biol. 2007;3:60-68. PMID:17143269

2: Structural and functional characterization of the transcriptional repressor CsoR from Thermus thermophilus HB8. Sakamoto K, Agari Y, Agari K, Kuramitsu S, Shinkai A; Microbiology. 2010;156:1993-2005. PMID:20395270

3: High-level resistance to cobalt and nickel but probably no transenvelope efflux: Metal resistance in the Cuban Serratia marcescens strain C-1. Marrero J, Auling G, Coto O, Nies DH; Microb Ecol. 2007;53:123-133. PMID:17186148

4: Nickel-resistant determinant from Leptospirillum ferriphilum. Tian J, Wu N, Li J, Liu Y, Guo J, Yao B, Fan Y; Appl Environ Microbiol. 2007;73:2364-2368. PMID:17293508

5: Nickel homeostasis in Escherichia coli - the rcnR-rcnA efflux pathway and its linkage to NikR function. Iwig JS, Rowe JL, Chivers PT; Mol Microbiol. 2006;62:252-262. PMID:16956381