1p6u

NMR structure of the BeF3-activated structure of the response regulator Chey2-Mg2+ from Sinorhizobium meliloti

spinqualitylabelsall models 1p6u Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1p6u is a 1 chain structure with sequence from Sinorhizobium meliloti. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q52884_RHIML 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 chemotactic signalling chain to the flagellar motor of Sinorhizobium meliloti features a new type of response regulator, CheY2. CheY2 activated by phosphorylation (CheY2-P) controls the rotary speed of the flagellar motor (instead of reversing the sense of rotation), and it is efficiently dephosphorylated by phospho-retrotransfer to the cognate kinase, CheA. Here, we report the NMR solution structures of the Mg(2+)-complex of inactive CheY2, and of activated CheY2-BeF(3), a stable analogue of CheY2-P, to an overall root mean square deviation of 0.042 nm and 0.027 nm, respectively. The 14 kDa CheY2 protein exhibits a characteristic open (alpha/beta)(5) conformation. Modification of CheY2 by BeF(3)(-) leads to large conformational changes of the protein, which are in the limits of error identical with those observed by phosphorylation of the active-centre residue Asp58. In BeF(3)-activated CheY2, the position of Thr88-OH favours the formation of a hydrogen bond with the active site, Asp58-BeF(3), similar to BeF(3)-activated CheY from Escherichia coli. In contrast to E.coli, this reorientation is not involved in a Tyr-Thr-coupling mechanism, that propagates the signal from the incoming phosphoryl group to the C-terminally located FliM-binding surface. Rather, a rearrangement of the Phe59 side-chain to interact with Ile86-Leu95-Val96 along with a displacement of alpha4 towards beta5 is stabilised in S.meliloti. The resulting, activation-induced, compact alpha4-beta5-alpha5 surface forms a unique binding domain suited for specific interaction with and signalling to a rotary motor that requires a gradual speed control. We propose that these new features of response regulator activation, compared to other two-component systems, are the key for the observed unique phosphorylation, dephosphorylation and motor control mechanisms in S.meliloti. Solution structures of the inactive and BeF3-activated response regulator CheY2.,Riepl H, Scharf B, Schmitt R, Kalbitzer HR, Maurer T J Mol Biol. 2004 Apr 23;338(2):287-97. PMID:15066432 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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