Protein Family Models

NikR is a transcription factor that regulates nickel uptake. It consists of two dimeric DNA binding domains separated by a tetrameric regulatory domain that binds nickel. This domain corresponds to the C terminal regulatory domain which contains four nickel binding sites at the tetramer interface [1]. [1]. 12970756. Crystal structure of the nickel-responsive transcription factor NikR. Schreiter ER, Sintchak MD, Guo Y, Chivers PT, Sauer RT, Drennan CL;. Nat Struct Biol. 2003;10:794-799. (from Pfam)

Date:

2024-10-16

The structure of this protein repressor, which is the shortest reported to date and the first isolated from a plasmid, has a homodimeric ribbon-helix-helix arrangement [2]. The helix-turn-helix-like structure is involved in dimerisation and not DNA binding as might have been expected [2]. [1]. 9714164. Structural features of the plasmid pMV158-encoded transcriptional repressor CopG, a protein sharing similarities with both helix-turn-helix and beta-sheet DNA binding proteins. Acebo P, Garcia de Lacoba M, Rivas G, Andreu JM, Espinosa M, del Solar G. Proteins 1998;32:248-261. [2]. 9857196. The structure of plasmid-encoded transcriptional repressor CopG unliganded and bound to its operator. Gomis-R th FX, Sol M, Acebo P, Parraga A, Guasch A, Eritja R, Gonzalez A, Espinosa M, del Solar G, Coll M. EMBO J 1998;17:7404-7415. (from Pfam)

Date:

2024-10-16

nickel-responsive transcriptional regulator NikR is a transcriptional repressor of the nikABCDE operon

Date:

2019-08-23

Inhibits transcription at high concentrations of nickel

Gene:

nikR

Date:

2021-10-15

Three members of the seed for this model, from Escherichia coli, Pseudomonas putida, and Brucella melitensis, are found associated with a nickel ABC transporter operon that acts to import nickel for use as a cofactor in urease or hydrogenase. These proteins, with characterized nickel-binding and DNA-binding domains, act as nickel-responsive transcriptional regulators. In the larger family of full-length homologs, most others both lack proximity to the nickel ABC transporter operon and form a separate clade. Several of the homologs not within the scope of this model, but rather scoring between the trusted and noise cutoffs, have been shown to bind nickel, copper, or both, and to regulate genes in response to nickel.

Gene:

nikR

Date:

2021-05-12

Inhibits transcription at high concentrations of nickel

Gene:

nikR

Date:

2021-11-04