PDBsum entry: 1a2o

Bacterial chemotaxis

PDB id: 1a2o

Contents

Protein chains

347 a.a. *

Waters ×411

* Residue conservation analysis

PDB id:

1a2o

Name:

Bacterial chemotaxis

Title:

Structural basis for methylesterase cheb regulation by a phosphorylation-activated domain

Structure:

Cheb methylesterase. Chain: a, b. Engineered: yes

Source:

Salmonella typhimurium. Organism_taxid: 602. Cellular_location: cytoplasm. Expressed in: escherichia coli. Expression_system_taxid: 562. Expression_system_cell: hb101.

Resolution:

2.40Å R-factor: 0.225

Authors:

S.Djordjevic,P.N.Goudreau,Q.Xu,A.M.Stock,A.H.West

Key ref:

S.Djordjevic et al. (1998). Structural basis for methylesterase CheB regulation by a phosphorylation-activated domain. Proc Natl Acad Sci U S A, 95, 1381-1386. PubMed id: 9465023 DOI: 10.1073/pnas.95.4.1381

Date:

06-Jan-98 Release date: 29-Apr-98

Protein chains

P04042  (CHEB_SALTY) -  Chemotaxis response regulator protein-glutamate methylesterase

Seq: 349 a.a.

Struc: 347 a.a.

Enzyme reactions

• Enzyme class: E.C.3.1.1.61 - Protein-glutamate methylesterase.
• Reaction: Protein L-glutamate O₅-methyl ester + H₂O = protein L-glutamate + methanol

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: cytoplasm (1 term)
• Biological process: intracellular signal transduction (4 terms)
• Biochemical function: hydrolase activity (3 terms)

reference

DOI no: 10.1073/pnas.95.4.1381

Proc Natl Acad Sci U S A 95:1381-1386 (1998)

PubMed id: 9465023

Structural basis for methylesterase CheB regulation by a phosphorylation-activated domain.

S.Djordjevic, P.N.Goudreau, Q.Xu, A.M.Stock, A.H.West.

ABSTRACT

We report the x-ray crystal structure of the methylesterase CheB, a phosphorylation-activated response regulator involved in reversible modification of bacterial chemotaxis receptors. Methylesterase CheB and methyltransferase CheR modulate signaling output of the chemotaxis receptors by controlling the level of receptor methylation. The structure of CheB, which consists of an N-terminal regulatory domain and a C-terminal catalytic domain joined by a linker, was solved by molecular replacement methods using independent search models for the two domains. In unphosphorylated CheB, the N-terminal domain packs against the active site of the C-terminal domain and thus inhibits methylesterase activity by directly restricting access to the active site. We propose that phosphorylation of CheB induces a conformational change in the regulatory domain that disrupts the domain interface, resulting in a repositioning of the domains and allowing access to the active site. Structural similarity between the two companion receptor modification enzymes, CheB and CheR, suggests an evolutionary and/or functional relationship. Specifically, the phosphorylated N-terminal domain of CheB may facilitate interaction with the receptors, similar to the postulated role of the N-terminal domain of CheR. Examination of surfaces in the N-terminal regulatory domain of CheB suggests that despite a common fold throughout the response regulator family, surfaces used for protein-protein interactions differ significantly. Comparison between CheB and other response regulators indicates that analogous surfaces are used for different functions and conversely, similar functions are mediated by different molecular surfaces.

Selected figure(s)

Figure 4.
Fig. 4. Structural comparison of the chemoreceptor modification enzymes. Structures of the methyltransferase CheR and the methylesterase^ CheB were aligned on the basis of similarity of their C-terminal domains by using a structural homology search in DALI (34). For both molecules, ribbon diagrams depict the N-terminal domains in blue, linker regions in gold, and C-terminal domains in green. The molecule of S-adenosylhomocysteine (SAH) in CheR and the methylesterase^ active site residues [Ser-164 (S), His-190 (H), and Asp-286(D)] in CheB are shown as CPK models. The double-headed arrow points toward the active sites and the receptor interaction openings. Functionally antagonistic CheB and CheR contain active sites on opposite faces of the structurally homologous central -sheets.

Figure 5.
Fig. 5. CPK model of the N-terminal domain of CheB, showing surfaces that are involved in protein-protein interactions among the response^ regulators CheB, CheY, and NarL. Residues involved in interaction with the C-terminal domain of CheB are colored yellow. Residues that have been implicated in protein-protein interactions in other response regulators are shown with colored mesh: red for corresponding residues in CheY that are thought to be involved in interaction with the P2 domain of the histidine kinase CheA (39); green for corresponding residues in NarL that interact with its C-terminal DNA-binding domain (25).

Figures were selected by an automated process.