ribbon-helix-helix domains of transcription repressor CopG, nickel responsive transcription factor NikR, and similar proteins; This family includes the ribbon-helix-helix (RHH) domains of transcriptional repressor CopG, nickel-responsive transcription factor NikR, several antitoxins such as Shewanella oneidensis CopA(SO), Burkholderia pseudomallei HicB, and Caulobacter crescentus ParD, and similar proteins. CopG, a homodimeric RHH protein of around 45 residues, constitutes one of the smallest natural transcriptional repressors characterized and is the prototype of a series of repressor proteins encoded by plasmids that exhibit a similar genetic structure at their leading strand initiation and control regions. It is involved in the control of plasmid copy number. NikR, which consists of the N-terminal DNA-binding RHH domain and the C-terminal metal-binding domain (MBD) with four nickel ions, regulates several genes; in Helicobacter pylori, NikR regulates the urease enzyme under extreme acidic conditions, and is involved in the intracellular physiology of nickel. Protein HicB is part of the HicAB toxin-antitoxin (TA) system, where the toxins are RNases, found in many bacteria. In Burkholderia pseudomallei, the HicAB system may play a role in disease by regulating the frequency of persister cells, while in Yersinia pestis HicB acts as an autoregulatory protein that inhibits HicA, which acts as an mRNase. In Escherichia coli, an excess of HicA has been shown to de-repress a HicB-DNA complex and restore transcription of HicB. The CopG family RHH domain, represented by this model, forms a homodimer and binds DNA.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 2787207760  6 KRLSVNISDDLDRLIDELADDAKITRADVVRRALAIMKAYKQ 47
Cdd:cd22235    1 KRITISLDEETKEILEELKKETGKSQSEIIRRALKFYYENRD 42

ribbon-helix-helix domain of CopG family transcriptional regulators found in archaea; This subfamily includes the N-terminal ribbon-helix-helix (RHH) domain of putative transcriptional repressor CopG from archaea, and similar proteins. These uncharacterized proteins have a typical RHH, similar to plasmid-encoded transcriptional repressor CopG, the protein that is encoded by the promiscuous streptococcal plasmid pMV158 and is involved in the control of plasmid copy number.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 2787207760  6 KRLSVNISDDLDRLIDELADDAKITRADVVRRALAIMKAYKQ 47
Cdd:cd22235    1 KRITISLDEETKEILEELKKETGKSQSEIIRRALKFYYENRD 42

ribbon-helix-helix domain of CopG family transcriptional regulators found in archaea; This subfamily includes the N-terminal ribbon-helix-helix (RHH) domain of putative transcriptional repressor CopG from archaea, and similar proteins. These uncharacterized proteins have a typical RHH, similar to plasmid-encoded transcriptional repressor CopG, the protein that is encoded by the promiscuous streptococcal plasmid pMV158 and is involved in the control of plasmid copy number.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 2787207760  6 KRLSVNISDDLDRLIDELADDAKITRADVVRRALAIMKAYKQ 47
Cdd:cd22235    1 KRITISLDEETKEILEELKKETGKSQSEIIRRALKFYYENRD 42

ribbon-helix-helix domains of transcription repressor CopG, nickel responsive transcription factor NikR, and similar proteins; This family includes the ribbon-helix-helix (RHH) domains of transcriptional repressor CopG, nickel-responsive transcription factor NikR, several antitoxins such as Shewanella oneidensis CopA(SO), Burkholderia pseudomallei HicB, and Caulobacter crescentus ParD, and similar proteins. CopG, a homodimeric RHH protein of around 45 residues, constitutes one of the smallest natural transcriptional repressors characterized and is the prototype of a series of repressor proteins encoded by plasmids that exhibit a similar genetic structure at their leading strand initiation and control regions. It is involved in the control of plasmid copy number. NikR, which consists of the N-terminal DNA-binding RHH domain and the C-terminal metal-binding domain (MBD) with four nickel ions, regulates several genes; in Helicobacter pylori, NikR regulates the urease enzyme under extreme acidic conditions, and is involved in the intracellular physiology of nickel. Protein HicB is part of the HicAB toxin-antitoxin (TA) system, where the toxins are RNases, found in many bacteria. In Burkholderia pseudomallei, the HicAB system may play a role in disease by regulating the frequency of persister cells, while in Yersinia pestis HicB acts as an autoregulatory protein that inhibits HicA, which acts as an mRNase. In Escherichia coli, an excess of HicA has been shown to de-repress a HicB-DNA complex and restore transcription of HicB. The CopG family RHH domain, represented by this model, forms a homodimer and binds DNA.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 2787207760  6 KRLSVNISDDLDRLIDELADDAKITRADVVRRalAIMKAYKQQ 48
Cdd:cd21631    1 KRVTIKLDDELLERLDELARKRGVSRSELIRE--ALREYLERL 41