1ujb
From Proteopedia
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Structure of the protein histidine phosphatase SixA
Overview
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.
About this Structure
1UJB is a Single protein structure of sequence from Escherichia coli with CA as ligand. Full crystallographic information is available from OCA.
Reference
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
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