Protein-glutamate methylesterase

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protein-glutamate methylesterase
EC number
CAS number 93792-01-9
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
PDB 1a2o EBI.jpg
structural basis for methylesterase cheb regulation by a phosphorylation-activated domain
Symbol CheB_methylest
Pfam PF01339
InterPro IPR000673
SCOP 1chd

In enzymology, a protein-glutamate methylesterase (EC is an enzyme that catalyzes the chemical reaction

protein L-glutamate O5-methyl ester + H2O protein L-glutamate + methanol

Thus, the two substrates of this enzyme are protein L-glutamate O5-methyl ester and H2O, whereas its two products are protein L-glutamate and methanol.

This enzyme is a demethylase, and more specifically it belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is protein-L-glutamate-O5-methyl-ester acylhydrolase. Other names in common use include chemotaxis-specific methylesterase, methyl-accepting chemotaxis protein methyl-esterase, CheB methylesterase, methylesterase CheB, protein methyl-esterase, protein carboxyl methylesterase, PME, protein methylesterase, and protein-L-glutamate-5-O-methyl-ester acylhydrolase. This enzyme participates in 3 metabolic pathways: two-component system - general, bacterial chemotaxis - general, and bacterial chemotaxis - organism-specific.

CheB is part of a two-component signal transduction system. These systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions.[1] Two-component systems are composed of a sensor histidine kinase (HK) and its cognate response regulator (RR).[2] The HK catalyses its own autophosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, in this case a methyltransferase domain.

CheB is involved in chemotaxis. CheB methylesterase is responsible for removing the methyl group from the gamma-glutamyl methyl ester residues in the methyl-accepting chemotaxis proteins (MCP). CheB is regulated through phosphorylation by CheA. The N-terminal region of the protein is similar to that of other regulatory components of sensory transduction systems.

Structural studies[edit]

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1A2O and 1CHD.


  1. ^ Skerker JM, Prasol MS, Perchuk BS, Biondi EG, Laub MT (October 2005). "Two-component signal transduction pathways regulating growth and cell cycle progression in a bacterium: a system-level analysis". PLoS Biol. 3 (10): e334. PMC 1233412Freely accessible. PMID 16176121. doi:10.1371/journal.pbio.0030334. 
  2. ^ Stock AM, Robinson VL, Goudreau PN (2000). "Two-component signal transduction". Annu. Rev. Biochem. 69: 183–215. PMID 10966457. doi:10.1146/annurev.biochem.69.1.183. 

Further reading[edit]

  • Kehry MR, Doak TG, Dahlquist FW (1984). "Stimulus-induced changes in methylesterase activity during chemotaxis in Escherichia coli". J. Biol. Chem. 259 (19): 11828–35. PMID 6384215. 

This article incorporates text from the public domain Pfam and InterPro IPR000673