1fqw
From Proteopedia
CRYSTAL STRUCTURE OF ACTIVATED CHEY
Structural highlights
Function[CHEY_ECOLI] Involved in the transmission of sensory signals from the chemoreceptors to the flagellar motors. In its active (phosphorylated or acetylated) form, CheY exhibits enhanced binding to a switch component, FliM, at the flagellar motor which induces a change from counterclockwise to clockwise flagellar rotation. Overexpression of CheY in association with MotA and MotB improves motility of a ycgR disruption, suggesting there is an interaction (direct or indirect) between the c-di-GMP-binding flagellar brake protein and the flagellar stator.[1] 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 PubMedThe crystal structure of BeF(3)(-)-activated CheY, with manganese in the magnesium binding site, was determined at 2.4-A resolution. BeF(3)(-) bonds to Asp(57), the normal site of phosphorylation, forming a hydrogen bond and salt bridge with Thr(87) and Lys(109), respectively. The six coordination sites for manganese are satisfied by a fluorine of BeF(3)(-), the side chain oxygens of Asp(13) and Asp(57), the carbonyl oxygen of Asn(59), and two water molecules. All of the active site interactions seen for BeF(3)(-)-CheY are also observed in P-Spo0A(r). Thus, BeF(3)(-) activates CheY as well as other receiver domains by mimicking both the tetrahedral geometry and electrostatic potential of a phosphoryl group. The aromatic ring of Tyr(106) is found buried within a hydrophobic pocket formed by beta-strand beta4 and helix H4. The tyrosine side chain is stabilized in this conformation by a hydrogen bond between the hydroxyl group and the backbone carbonyl oxygen of Glu(89). This hydrogen bond appears to stabilize the active conformation of the beta4/H4 loop. Comparison of the backbone coordinates for the active and inactive states of CheY reveals that only modest changes occur upon activation, except in the loops, with the largest changes occurring in the beta4/H4 loop. This region is known to be conformationally flexible in inactive CheY and is part of the surface used by activated CheY for binding its target, FliM. The pattern of activation-induced backbone coordinate changes is similar to that seen in FixJ(r). A common feature in the active sites of BeF(3)(-)-CheY, P-Spo0A(r), P-FixJ(r), and phosphono-CheY is a salt bridge between Lys(109) Nzeta and the phosphate or its equivalent, beryllofluoride. This suggests that, in addition to the concerted movements of Thr(87) and Tyr(106) (Thr-Tyr coupling), formation of the Lys(109)-PO(3)(-) salt bridge is directly involved in the activation of receiver domains generally. Crystal structure of activated CheY. Comparison with other activated receiver domains.,Lee SY, Cho HS, Pelton JG, Yan D, Berry EA, Wemmer DE J Biol Chem. 2001 May 11;276(19):16425-31. Epub 2001 Feb 13. PMID:11279165[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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