Nickel-responsive transcriptional regulator NikR (NikR)

Nickel-responsive transcriptional regulator NikR is a bacterial transcription factor that controls the expression of the nik operon, which encodes nickel transport systems. NikR is activated by direct binding of nickel ions to a central metal-binding domain, resulting in a conformational change that enables the protein to bind operator DNA and repress transcription of target genes. The protein functions as a tetramer, with two dimeric ribbon–helix–helix domains that recognize operator DNA, and a central tetrameric metal-binding core where nickel ions coordinate at the interface of subunits. By sensing cytosolic nickel levels, NikR maintains nickel homeostasis, which is essential for the catalytic activity of specific bacterial enzymes (e.g., hydrogenases, ureases)[1]. Targeting NikR, or disrupting its activity, could affect bacterial nickel uptake and survival, making it a potential antimicrobial target in pathogens where nickel import and regulation are essential for viability.

Other names

Nickel uptake regulatorNickel-responsive transcription factor

Allosteric regulation by nickel ion binding; Conformational switch for operator DNA repression