PDBsum entry 1ehc

Signal transduction

PDB id: 1ehc

Contents

Protein chain

128 a.a. *

Ligands

SO4

Waters ×100

* Residue conservation analysis

PDB id:

1ehc

Name:

Signal transduction

Title:

Structure of signal transduction protein chey

Structure:

Chey. Chain: a. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Expressed in: escherichia coli. Expression_system_taxid: 562. Other_details: naturally-occurring mutant

Resolution:

2.26Å R-factor: 0.143

Authors:

M.Jiang,R.Bourret,M.Simon,K.Volz

Key ref:

M.Jiang et al. (1997). Uncoupled phosphorylation and activation in bacterial chemotaxis. The 2.3 A structure of an aspartate to lysine mutant at position 13 of CheY. J Biol Chem, 272, 11850-11855. PubMed id: 9115243 DOI: 10.1074/jbc.272.18.11850

Date:

05-Mar-96 Release date: 15-May-97

Protein chain

P0AE67  (CHEY_ECOLI) -  Chemotaxis protein CheY from Escherichia coli (strain K12)

Seq: 129 a.a.

Struc: 128 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.272.18.11850

J Biol Chem 272:11850-11855 (1997)

PubMed id: 9115243

Uncoupled phosphorylation and activation in bacterial chemotaxis. The 2.3 A structure of an aspartate to lysine mutant at position 13 of CheY.

M.Jiang, R.B.Bourret, M.I.Simon, K.Volz.

ABSTRACT

An aspartate to lysine mutation at position 13 of the chemotaxis regulatory protein CheY causes a constitutive tumbly phenotype when expressed at high copy number in vivo even though the mutant protein is not phosphorylatable. These properties suggest that the D13K mutant adopts the active, signaling conformation of CheY independent of phosphorylation, so knowledge of its structure could explain the activation mechanism of CheY. The x-ray crystallographic structure of the CheY D13K mutant has been solved and refined at 2.3 A resolution to an R-factor of 14.3%. The mutant molecule shows no significant differences in backbone conformation when compared with the wild-type, Mg2+-free structure, but there are localized changes within the active site. The side chain of lysine 13 blocks access to the active site, whereas its epsilon-amino group has no bonding interactions with other groups in the region. Also in the active site, the bond between lysine 109 and aspartate 57 is weakened, and the solvent structure is perturbed. Although the D13K mutant has the inactive conformation in the crystalline form, rearrangements in the active site appear to weaken the overall structure of that region, potentially creating a metastable state of the molecule. If a conformational change is required for signaling by CheY D13K, then it most likely proceeds dynamically, in solution.

Selected figure(s)

Figure 4.
Fig. 4. Comparison of CheY active sites. A, active site of wild-type CheY at 1.7 Å resolution (14). B, active site of CheY D13K at 2.3 Å resolution. The orientation is approximately the^ same as in Fig. 2. The solvent molecules are numbered in order of increasing temperature factors for each structure.

Figure 5.
Fig. 5. Schematic diagram of possible activation pathways for wild-type CheY and CheY D13K.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (1997, 272, 11850-11855) copyright 1997.

Figures were selected by an automated process.