Structural highlights
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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Riepl H, Scharf B, Schmitt R, Kalbitzer HR, Maurer T. Solution structures of the inactive and BeF3-activated response regulator CheY2. J Mol Biol. 2004 Apr 23;338(2):287-97. PMID:15066432 doi:10.1016/j.jmb.2004.02.054
