Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An enzyme of molecular weight 32,000 comprising a single subunit has been isolated from whole cell extracts of the yeast Saccharomyces cerevisiae. In vitro, the enzyme transfers the gamma phosphate of ATP to a protein substrate, histone H4, to produce an alkali-stable phosphorylation. Modification of the substrate histidine with diethylpyrocarbonate prevented phosphorylation. Phosphoamino acid analysis of the phosphorylated substrate showed the presence of 1-phosphohistidine. Hence, the isolated enzyme is a protein histidine kinase. A novel assay for acid-labile alkali-stable protein phosphorylation was used in the purification of the kinase activity to a final specific activity of 2,700 nmol/15 min/mg. The purified enzyme phosphorylates specifically histidine 75 in histone H4 and does not phosphorylate histidine 18 nor histidine residues in any other core histone. Steady state kinetic data are consistent with an ordered sequential reaction with Km values for Mg-ATP and histone H4 of 60 and 17 microM, respectively. The protein histidine kinase requires a divalent cation such as Mg2+, Co2+, or Mn2+ but will not use Ca2+, Zn2+, Cu2+, Fe2+, spermine, or spermidine. This is the first purification of an enzyme that catalyzes N-linked phosphorylation in proteins.
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PMID:Purification of a protein histidine kinase from the yeast Saccharomyces cerevisiae. The first member of this class of protein kinases. 202 10

Protein histidine kinase (Motojima, K., and Goto, S. (1993) FEBS Lett. 319, 75-79) and phosphatase in rat liver extract were characterized. The histidine kinase was recovered mostly in the membrane and the phosphatase in the soluble fraction. The kinase and its substrate 36-kDa protein (P36) were co-solubilized from the membrane under conditions in which most of the other kinases, and their substrate proteins were not solubilized. The solubilized kinase and P36 were co-eluted after high pressure liquid chromatography gel filtration, showing an apparent molecular mass of 70-75 kDa. They were also co-eluted after ion exchange chromatography. These characteristics, together with its complete resistance to genistein, indicate that the rat liver histidine kinase is not cognate to the yeast enzyme (Huang, J., Nasr, M., Kim, Y., and Matthews, H.R. (1992) J. Biol. Chem. 267, 15511-15515). The phosphatase that dephosphorylates histidyl-phosphorylated P36 was also studied using rat liver subcellular fractions and in vitro phosphorylated P36 as the substrate. The characteristics of the phosphatase, that is, 1) Mg2+ requirement for activity, 2) apparent molecular mass of 45 kDa by high performance liquid chromatography gel filtration, and 3) resistance to 100 microM okadaic acid, suggest that the primary phosphatase active in vitro is protein phosphatase 2C.
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PMID:Histidyl phosphorylation and dephosphorylation of P36 in rat liver extract. 813 40

EnvZ of Escherichia coli is a transmembrane histidine kinase belonging to the family of two-component signal transducing systems prevalent in prokaryotes and recently discovered in eukaryotes. In response to changes in medium osmolarity EnvZ regulates the level of phosphorylated OmpR, its conjugate response-regulating transcription factor for ompF and ompC genes. EnvZ has dual opposing enzymatic activities; OmpR-phosphorylase (kinase) and phospho-OmpR-dephosphorylase (phosphatase). The osmotic signal is proposed to regulate the ratio of the kinase to the phosphatase activities of EnvZ to modulate the level of OmpR phosphorylation. In this work we used a COOH-terminal fragment of a previously identified kinase-/phosphatase+ EnvZ mutant (EnvZ-N347D) to demonstrate that the phosphoryl group on phospho-OmpR is transferred back to EnvZ to the same histidine residue (His243) that is utilized for the autokinase reaction by the wild type protein. Phospho-EnvZ-N347D thus formed could also transfer its phosphoryl group back to OmpR. The phosphotransfer reaction from phospho-OmpR to EnvZ.N347D was inhibited by ADP while Mg2+ ions stimulated the dephosphorylation reaction, resulting in release of inorganic phosphate. These results indicate that the energy levels of phosphoryl groups on OmpR and EnvZ are very similar and that the phosphatase reaction in the EnvZ.N347D mutant involves a reversal of the phosphotransfer reaction from EnvZ to OmpR using the identical His243 residue.
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PMID:Reverse phosphotransfer from OmpR to EnvZ in a kinase-/phosphatase+ mutant of EnvZ (EnvZ.N347D), a bifunctional signal transducer of Escherichia coli. 857 33

The central signaling pathway in many bacterial regulatory systems involves phosphotransfer between two conserved proteins, a histidine protein kinase, and a response regulator. The occurrence of two-component signaling systems in thermophilic bacteria raises questions of how both the proteins and the labile acyl phosphate of the response regulator are adapted to function at elevated temperatures. Thermotoga maritima HpkA is a transmembrane histidine kinase, and DrrA is its cognate response regulator. Both DrrA and the cytoplasmic region of HpkA (HpkA57) have been expressed in Escherichia coli, purified, and characterized. HpkA57 and DrrA have apparent Tm's of 75 and 90 degreesC, respectively. HpkA57 exhibits ATP-dependent autophosphorylation activity similar to that of histidine kinases from mesophiles, with maximum activity at 70 degreesC. DrrA catalyzes transfer of phosphoryl groups from HpkA57 and exhibits Mg2+-dependent autophosphatase activity, with maximum activity at approximately 80 degreesC. At this temperature, the half-life for phospho-DrrA is approximately 3 min. In the absence of Mg2+, the half-life is 26 min, significantly greater than the half-life of a typical acyl phosphate at 80 degreesC. In the absence of Mg2+, at all temperatures examined, phospho-DrrA exhibits much greater stability than acetyl phosphate. This suggests that the active site of this hyperthermophilic response regulator is designed to protect the phospho-aspartyl residue from hydrolysis.
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PMID:Stabilization of the phospho-aspartyl residue in a two-component signal transduction system in Thermotoga maritima. 977 86

In two-component signaling systems, the transduction strategy relies on a conserved His-Asp phosphoryl exchange between the sensor histidine kinase and its cognate response-regulator, and structural and functional consensus motifs are found when comparing either the diverse histidine kinases or response regulators present in a single cell. Therefore, the mechanism that guarantees the specific recognition between partners of an individual pair is essential to unequivocally generate the appropriate adaptive response. Based on sequence alignments with other histidine kinases, we dissected the Salmonella enterica Mg2+-sensor PhoQ in different subdomains and examined by in vivo and in vitro assays its interaction with the associated response regulator PhoP. This signal transduction system allows Salmonella to withstand environmental Mg2+ limitation by triggering gene expression that is vital throughout the infective cycle in the host. Using resonant mirror biosensor technology, we calculated the kinetic and equilibrium binding constants and determined that the His-phosphotransfer domain is essential for the PhoQ specific recognition and interaction with PhoP. Additionally, we show the role of this domain in the bimolecular transphosphorylation and provide evidence that this region undergoes dimerization.
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PMID:The H box-harboring domain is key to the function of the Salmonella enterica PhoQ Mg2+-sensor in the recognition of its partner PhoP. 1270 18

Receptors for the gaseous phytohormone ethylene show sequence similarity to bacterial two-component histidine kinases. These receptors are encoded by a multigene family that can be divided into subfamilies 1 and 2. It has been previously shown that a subfamily 1 Arabidopsis thaliana ethylene receptor, ETR1, autophosphorylates in vitro on a conserved histidine residue (1). However, sequence comparisons between the five ethylene receptor family members suggest that subfamily 2 members do not have all the motifs necessary for histidine kinase activity. Further, a tobacco subfamily 2 receptor, NTHK1, autophosphorylates on serines and threonines in vitro (2). Here we show that all five Arabidopsis ethylene receptor proteins autophosphorylate in vitro. We analyzed the nature of the phosphorylated amino acids by acid/base stability and bi-dimensional thin layer electrophoresis and demonstrated that unlike ETR1 all other ethylene receptors autophosphorylate predominantly on serine residues. ERS1, the only other subfamily 1 receptor, is able to phosphorylate on both histidine and serine residues in the presence of Mn2+. However, histidine autophosphorylation is lost when ERS1 is assayed in the presence of both Mg2+ and Mn2+, suggesting that this activity may not occur in vivo. Furthermore, mutation of the histidine residue conserved in two-component systems does not abolish serine autophosphorylation, eliminating the possibility of a histidine to serine phosphotransfer. Our biochemical observations complement the recently published genetic data that histidine kinase activity is not necessary for ethylene receptor function in plants and suggest that ethylene signal transduction does not occur through a phosphorelay mechanism.
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PMID:Autophosphorylation activity of the Arabidopsis ethylene receptor multigene family. 1535 68

Two-component signal-transduction systems are widespread in bacteria. They are usually composed of a transmembrane histidine kinase sensor and a cytoplasmic response regulator. The PhoP/PhoQ two-component system of Salmonella typhimurium contributes to virulence by co-ordinating the adaptation to low concentrations of environmental Mg2+. Limiting concentrations of extracellular Mg2+ activate the PhoP/PhoQ phosphorylation cascade modulating the transcription of PhoP-regulated genes. In contrast, high concentrations of extracellular Mg2+ stimulate the dephosphorylation of the response regulator PhoP by the PhoQ kinase sensor. In the present study, we report the purification and functional reconstitution of PhoQ(His), a PhoQ variant with a C-terminal His tag, into Escherichia coli liposomes. The functionality of PhoQ(His) was essentially similar to that of PhoQ as shown in vivo and in vitro. Purified PhoQ(His) was inserted into liposomes in a unidirectional orientation, with the sensory domain facing the lumen and the catalytic domain facing the extraluminal environment. Reconstituted PhoQ(His) exhibited all the catalytic activities that have been described for histidine kinase sensors. Reconstituted PhoQ(His) was capable of autokinase activity when incubated in the presence of Mg2+-ATP. The phosphoryl group could be transferred from reconstituted PhoQ(His) to PhoP. Reconstituted PhoQ(His) catalysed the dephosphorylation of phospho-PhoP and this activity was stimulated by the addition of extraluminal ADP.
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PMID:Functional reconstitution of the Salmonella typhimurium PhoQ histidine kinase sensor in proteoliposomes. 1591 Feb 83

We report the identification of a novel two-component system in Mycobacterium tuberculosis. We show that the putative histidine kinase with the genomic locus tag Rv3220c is able to self-phosphorylate in the presence of Mg2+/ATP and subsequently transfer the phosphoryl group to a novel response regulator PdtaR. This creates a biochemical link between the two proteins and establishes a newly identified two component system, which acts at the level of transcriptional antitermination. We also suggest that this system has potential for the development of lead compounds for inhibition of phosphotransfer.
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PMID:A novel two-component system found in Mycobacterium tuberculosis. 1602 86

The Rcs signalling pathway controls a variety of physiological functions like capsule synthesis, cell division or motility in prokaryotes. The Rcs regulation cascade, involving a multi-step phosphorelay between the two membrane-bound hybrid sensor kinases RcsC and RcsD and the global regulator RcsB, is, up to now, one of the most complicated regulatory systems in bacteria. To understand the structural basis of Rcs signal transduction, NMR spectroscopy was employed to determine the solution structure of the RcsC C terminus, possessing a phosphoreceiver domain (RcsC-PR), and a region previously described as a long linker between the histidine kinase domain of RcsC (RcsC-HK) and the RcsC-PR. We have found that the linker region comprises an independent structural domain of a new alpha/beta organization, which we named RcsC-ABL domain (Alpha/Beta/Loop). The ABL domain appears to be a conserved and unique structural element of RcsC-like kinases with no significant sequence homology to other proteins. The second domain of the C terminus, the RcsC-PR domain, represents a well-folded CheY-like phosphoreceiver domain with the central parallel beta-sheet covered with two alpha-helical layers on both sides. We have mapped the interaction of RcsC-ABL and RcsC-PR with the histidine phosphotransfer domain (HPt) of RcsD. In addition we have characterized the interaction with and the conformational effects of Mg2+ and the phosphorylation mimetic BeF(-)(3) on RcsC-ABL and RcsC-PR.
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PMID:A new structural domain in the Escherichia coli RcsC hybrid sensor kinase connects histidine kinase and phosphoreceiver domains. 1700 98

The PhoP-PhoQ two-component system is a well studied bacterial signaling system that regulates virulence and stress response. Catalytic activity of the histidine kinase sensor protein PhoQ is activated by low extracellular concentrations of divalent cations such as Mg2+, and subsequently the response regulator PhoP is activated in turn through a classic phosphotransfer pathway that is typical in such systems. The PhoQ sensor domains of enteric bacteria contain an acidic cluster of residues (EDDDDAE) that has been implicated in direct binding to divalent cations. We have determined crystal structures of the wild-type Escherichia coli PhoQ periplasmic sensor domain and of a mutant variant in which the acidic cluster was neutralized to conservative uncharged residues (QNNNNAQ). The PhoQ domain structure is similar to that of DcuS and CitA sensor domains, and this PhoQ-DcuS-CitA (PDC) sensor fold is seen to be distinct from the superficially similar PAS domain fold. Analysis of the wild-type structure reveals a dimer that allows for the formation of a salt bridge across the dimer interface between Arg-50' and Asp-179 and with nickel ions bound to aspartate residues in the acidic cluster. The physiological importance of the salt bridge to in vivo PhoQ function has been confirmed by mutagenesis. The mutant structure has an alternative, non-physiological dimeric association.
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PMID:Crystal structure of a functional dimer of the PhoQ sensor domain. 1834 79


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