Histidine Phosphotransfer domain, involved in signalling through a two part component systems in which an autophosphorylating histidine protein kinase serves as a phosphoryl donor to a response regulator protein; the response regulator protein is modulated by phosphorylation and dephosphorylation of a conserved aspartic acid residue; two-component proteins are abundant in most eubacteria; In E. coli there are 62 two-component proteins involved in a variety of processes such as chemotaxis, osmoregulation, metabolism and transport 1; also present in both Gram positive and Gram negative pathogenic bacteria where they regulate basic housekeeping functions and control expression of toxins and other proteins important for pathogenesis; in archaea and eukaryotes, two-component pathways constitute a very small number of all signaling systems; in fungi they mediate environmental stress responses and, in pathogenic yeast, hyphal development. In Dictyostelium and in plants, they are involved in important processes such as osmoregulation, cell growth, and differentiation; to date two-component proteins have not been identified in animals; in most prokaryotic systems, the output response is effected directly by the RR, which functions as a transcription factor while in eukaryotic systems, two-component proteins are found at the beginning of signaling pathways where they interface with more conventional eukaryotic signaling strategies such as MAP kinase and cyclic nucleotide cascades

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1087961098  59 EEFVGEAEDTLEQLKIDLDGLkgsfvTGQKDKEveivlRIFRNLHTLKGVASLFGFNQFSTISFTLENYFDALRMDKAKL 138
Cdd:cd00088     6 ELFLEEAEELLEELERALLEL-----EDAEDLN-----EIFRAAHTLKGSAASLGLQRLAQLAHQLEDLLDALRDGLEVT 75

                  .
gi 1087961098 139 S 139
Cdd:cd00088    76 P 76

Hpt domain; The histidine-containing phosphotransfer (HPt) domain is a novel protein module with an active histidine residue that mediates phosphotransfer reactions in the two-component signaling systems. A multistep phosphorelay involving the HPt domain has been suggested for these signaling pathways. The crystal structure of the HPt domain of the anaerobic sensor kinase ArcB has been determined. The domain consists of six alpha helices containing a four-helix bundle-folding. The pattern of sequence similarity of the HPt domains of ArcB and components in other signaling systems can be interpreted in light of the three-dimensional structure and supports the conclusion that the HPt domains have a common structural motif both in prokaryotes and eukaryotes. In S. cerevisiae ypd1p this domain has been shown to contain a binding surface for Ssk1p (response regulator receiver domain containing protein pfam00072).

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1087961098  59 EEFVGEAEDTLEQLKIDLDGlkgsfvtgqkdkevEIVLRIFRNLHTLKGVASLFGFNQFSTISFTLENYFDALRMD 134
Cdd:pfam01627   4 ELFLEEAPELLEQLEQALDA--------------EDLEALFRAAHTLKGSAGSLGLPALAELAHELEDLLREGELP 65

Histidine Phosphotransfer domain, involved in signalling through a two part component systems in which an autophosphorylating histidine protein kinase serves as a phosphoryl donor to a response regulator protein; the response regulator protein is modulated by phosphorylation and dephosphorylation of a conserved aspartic acid residue; two-component proteins are abundant in most eubacteria; In E. coli there are 62 two-component proteins involved in a variety of processes such as chemotaxis, osmoregulation, metabolism and transport 1; also present in both Gram positive and Gram negative pathogenic bacteria where they regulate basic housekeeping functions and control expression of toxins and other proteins important for pathogenesis; in archaea and eukaryotes, two-component pathways constitute a very small number of all signaling systems; in fungi they mediate environmental stress responses and, in pathogenic yeast, hyphal development. In Dictyostelium and in plants, they are involved in important processes such as osmoregulation, cell growth, and differentiation; to date two-component proteins have not been identified in animals; in most prokaryotic systems, the output response is effected directly by the RR, which functions as a transcription factor while in eukaryotic systems, two-component proteins are found at the beginning of signaling pathways where they interface with more conventional eukaryotic signaling strategies such as MAP kinase and cyclic nucleotide cascades

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1087961098  59 EEFVGEAEDTLEQLKIDLDGLkgsfvTGQKDKEveivlRIFRNLHTLKGVASLFGFNQFSTISFTLENYFDALRMDKAKL 138
Cdd:cd00088     6 ELFLEEAEELLEELERALLEL-----EDAEDLN-----EIFRAAHTLKGSAASLGLQRLAQLAHQLEDLLDALRDGLEVT 75

                  .
gi 1087961098 139 S 139
Cdd:cd00088    76 P 76

Hpt domain; The histidine-containing phosphotransfer (HPt) domain is a novel protein module with an active histidine residue that mediates phosphotransfer reactions in the two-component signaling systems. A multistep phosphorelay involving the HPt domain has been suggested for these signaling pathways. The crystal structure of the HPt domain of the anaerobic sensor kinase ArcB has been determined. The domain consists of six alpha helices containing a four-helix bundle-folding. The pattern of sequence similarity of the HPt domains of ArcB and components in other signaling systems can be interpreted in light of the three-dimensional structure and supports the conclusion that the HPt domains have a common structural motif both in prokaryotes and eukaryotes. In S. cerevisiae ypd1p this domain has been shown to contain a binding surface for Ssk1p (response regulator receiver domain containing protein pfam00072).

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1087961098  59 EEFVGEAEDTLEQLKIDLDGlkgsfvtgqkdkevEIVLRIFRNLHTLKGVASLFGFNQFSTISFTLENYFDALRMD 134
Cdd:pfam01627   4 ELFLEEAPELLEQLEQALDA--------------EDLEALFRAAHTLKGSAGSLGLPALAELAHELEDLLREGELP 65