1u8t

From Proteopedia

Revision as of 13:21, 21 February 2008

Crystal structure of CheY D13K Y106W alone and in complex with a FliM peptide

Overview

CheY is a member of the response regulator protein superfamily that controls the chemotactic swimming response of motile bacteria. The CheY double mutant D13K Y106W (CheY**) is resistant to phosphorylation, yet is a highly effective mimic of phosphorylated CheY in vivo and in vitro. The conformational attributes of this protein that enable it to signal in a phosphorylation-independent manner are unknown. We have solved the crystal structure of selenomethionine-substituted CheY** in the presence of its target, a peptide (FliM16) derived from the flagellar motor switch, FliM, to 1.5A resolution with an R-factor of 19.6%. The asymmetric unit contains four CheY** molecules, two with FliM16 bound, and two without. The two CheY** molecules in the asymmetric unit that are bound to FliM16 adopt a conformation similar to BeF3- -activated wild-type CheY, and also bind FliM16 in a nearly identical manner. The CheY** molecules that do not bind FliM16 are found in a conformation similar to unphosphorylated wild-type CheY, suggesting that the active phenotype of this mutant is enabled by a facile interconversion between the active and inactive conformations. Finally, we propose a ligand-binding model for CheY and CheY**, in which Ile95 changes conformation in a Tyr/Trp106-dependent manner to accommodate FliM.

About this Structure

1U8T is a Protein complex structure of sequences from Escherichia coli with as ligand. Full crystallographic information is available from OCA.

Reference

Structure of the constitutively active double mutant CheYD13K Y106W alone and in complex with a FliM peptide., Dyer CM, Quillin ML, Campos A, Lu J, McEvoy MM, Hausrath AC, Westbrook EM, Matsumura P, Matthews BW, Dahlquist FW, J Mol Biol. 2004 Sep 24;342(4):1325-35. PMID:15351654

Page seeded by OCA on Thu Feb 21 15:21:49 2008