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156 a.a.
_CA
Key reference
DOI no: 10.1111/j.1365-2443.2005.00817.x Genes Cells 10:1 (2005) PubMed id: 15670209
Crystal structure of the protein histidine phosphatase SixA in the multistep His-Asp phosphorelay. K.Hamada, M.Kato, T.Shimizu, K.Ihara, T.Mizuno, T.Hakoshima. ABSTRACT
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.
Literature references that cite this PDB file's key reference
PubMed id Reference
18398008 Z.Lu, D.Dunaway-Mariano, and K.N.Allen (2008).
The catalytic scaffold of the haloalkanoic acid dehalogenase enzyme superfamily acts as a mold for the trigonal bipyramidal transition state.Proc Natl Acad Sci U S A, 105, 5687-5692.
PDB codes: 2rar 2rav 2rb5 2rbk
17348005 L.Davies, I.P.Anderson, P.C.Turner, A.D.Shirras, H.H.Rees, and D.J.Rigden (2007).
An unsuspected ecdysteroid/steroid phosphatase activity in the key T-cell regulator, Sts-1: surprising relationship to insect ecdysteroid phosphate phosphatase.Proteins, 67, 720-731. The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.
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