1ujb

Structure of the protein histidine phosphatase SixA

spinqualitylabelsall models 1ujb, resolution 2.06Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ujb is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA Related: 1ujc Resources: FirstGlance, OCA, RCSB, PDBsum Function [SIXA_ECOLI] Exhibits phosphohistidine phosphatase activity towards the HPt domain of the ArcB sensor involved in the multistep His-Asp phosphorelay. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The multiple histidine-aspartate phosphorelay system plays a crucial role in cellular adaptation to environments in microorganisms and plants. Like kinase-phosphatase systems in higher eukaryotes, the multiple steps provide additional regulatory checkpoints with phosphatases. The Escherichia coli phosphatase SixA exhibits protein phosphatase activity against the histidine-containing phosphotransfer (HPt) domain located in the C-terminus of the histidine kinase ArcB engaged in anaerobic responses. We have determined the crystal structures of the free and tungstate-bound forms of SixA at 2.06 A and 1.90 A resolution, respectively. The results provide the first three-dimensional view of a bacterial protein histidine phosphatase, revealing a compact alpha/beta architecture related to a family of phosphatases containing the arginine-histidine-glycine (RHG) motif at their active sites. Compared with these RHG phosphatases, SixA lacks an extra alpha-helical subdomain as a lid over the active site, thereby forming a relatively shallow groove important for the accommodation of the HPt domain of ArcB. The tungstate ion, which mimics the substrate phosphate group, is located at the centre of the active site where the active residue, His8, points to the tungsten atom in the mode of in-line nucleophilic attack. Crystal structure of the protein histidine phosphatase SixA in the multistep His-Asp phosphorelay.,Hamada K, Kato M, Shimizu T, Ihara K, Mizuno T, Hakoshima T Genes Cells. 2005 Jan;10(1):1-11. PMID:15670209 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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