Cloned (Comment) | Organism |
---|---|
gene slr1147, recombinant expression of C-terminally poly-His-tagged full-length enzyme in Escherichia coli strain BL21(DE3) | Synechocystis sp. PCC 6803 |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
additional information | upon salt and/or hyperosmotic signal, the activity of Hik2 is inhibited. KCl does not inhibit the autophosphorylation activity of Hik2 | Synechocystis sp. PCC 6803 | |
Na+ | strongly inhibits the autophosphorylation activity of Hik2. 0.5 M NaCl reduces the organism's growth rate by 50% | Synechocystis sp. PCC 6803 |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
cytoplasm | - |
Synechocystis sp. PCC 6803 | 5737 | - |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + protein L-histidine | Synechocystis sp. PCC 6803 | - |
ADP + protein N-phospho-L-histidine | - |
? | |
additional information | Synechocystis sp. PCC 6803 | interaction of Hik2 with Rre1 and RppA, usage of recombinant N-terminally MBP-tagged proteins purified from Escherichia coli expression host | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Synechocystis sp. PCC 6803 | P73276 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
phosphoprotein | Hik2 undergoes autophosphorylation on a conserved histidine residue, at pH 7.5 and 22°C, and becomes rapidly dephosphorylated by the action of response regulators Rre1 and RppA (regulator of phycobilisome association), at pH 7.5 and 30°C. The autophosphorylation of Hik2 is specifically inhibited by sodium ions | Synechocystis sp. PCC 6803 |
Purification (Comment) | Organism |
---|---|
recombinant C-terminally poly-His-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography and desalting gel filtration. Overexpression of te GST-tagged enzyme in a bait and prey two hybrid system in Saccharomyces cerevisiae | Synechocystis sp. PCC 6803 |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + protein L-histidine | - |
Synechocystis sp. PCC 6803 | ADP + protein N-phospho-L-histidine | - |
? | |
additional information | interaction of Hik2 with Rre1 and RppA, usage of recombinant N-terminally MBP-tagged proteins purified from Escherichia coli expression host | Synechocystis sp. PCC 6803 | ? | - |
? | |
additional information | during autophosphorylation, histidine kinases catalyze transfer of only the gamma-phosphate from an ATP molecule to their conserved histidine residue | Synechocystis sp. PCC 6803 | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
Hik2 | - |
Synechocystis sp. PCC 6803 |
histidine kinase | - |
Synechocystis sp. PCC 6803 |
sensory transduction histidine kinase | UniProt | Synechocystis sp. PCC 6803 |
slr1147 | - |
Synechocystis sp. PCC 6803 |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
ATP | the ATP-binding domain of histidine kinases contains conserved motifs essential for autokinase activity. These include G1 and G2 boxes, which have the characteristic glycine signatures DxGxG and GxGxG, respectively | Synechocystis sp. PCC 6803 |
General Information | Comment | Organism |
---|---|---|
metabolism | proposed signal transduction pathway for the Hik2-based two-component system in cyanobacteria, overview | Synechocystis sp. PCC 6803 |
physiological function | Hik2 is the cytoplasmic homologue of chloroplast sensor kinase (CSK), a protein involved in redox regulation of chloroplast gene expression during changes in light quality in plants and algae. Hik2 is the sensor that acts on Rre1 and RppA transcription factors to regulate photosynthesis genes as part of the mechanism of photosystem stoichiometry adjustment in cyanobacteria. Signaling mechanism of Hik2 and its phosphotransferase activity, overview. Hik2-based signaling pathway integrates acclimatory responses to light and salt stresses in cyanobacteria | Synechocystis sp. PCC 6803 |