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4  structures 1959  species 2  interactions 3655  sequences 120  architectures

Family: CheB_methylest (PF01339)

Summary: CheB methylesterase

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This is the Wikipedia entry entitled "Protein-glutamate methylesterase". More...

Protein-glutamate methylesterase Edit Wikipedia article

protein-glutamate methylesterase
Identifiers
EC number 3.1.1.61
CAS number 93792-01-9
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
CheB_methylest
PDB 1a2o EBI.jpg
structural basis for methylesterase cheb regulation by a phosphorylation-activated domain
Identifiers
Symbol CheB_methylest
Pfam PF01339
InterPro IPR000673
SCOP 1chd
SUPERFAMILY 1chd

In enzymology, a protein-glutamate methylesterase (EC 3.1.1.61) is an enzyme that catalyzes the chemical reaction

protein L-glutamate O5-methyl ester + H2O \rightleftharpoons 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.


References[edit]

  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. doi:10.1371/journal.pbio.0030334. PMC 1233412. PMID 16176121. 
  2. ^ Stock AM, Robinson VL, Goudreau PN (2000). "Two-component signal transduction". Annu. Rev. Biochem. 69: 183–215. doi:10.1146/annurev.biochem.69.1.183. PMID 10966457. 

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


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Literature references

  1. West AH, Martinez-Hackert E, Stock AM; , J Mol Biol 1995;250:276-290.: Crystal structure of the catalytic domain of the chemotaxis receptor methylesterase, CheB. PUBMED:7608974 EPMC:7608974


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000673

Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions [PUBMED:16176121]. Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk [PUBMED:18076326]. These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more [PUBMED:12372152]. Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR) [PUBMED:10966457]. The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.

A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response [PUBMED:11934609, PUBMED:11489844].

This entry represents the signal transduction response regulator CheB 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). The enzyme catalyses the reaction: protein L-glutamate O-methyl ester and water is converted to protein L-glutamate and methanol. 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. The Myxococcus xanthus FrzG protein also belongs to this family, and is required for the normal aggregation of cells during fruiting body formation.

Gene Ontology

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Domain organisation

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Alignments

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Meta
(363)
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(399)
RP35
(770)
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  Seed
(180)
Full
(3655)
Representative proteomes NCBI
(3093)
Meta
(363)
RP15
(399)
RP35
(770)
RP55
(1013)
RP75
(1223)
Alignment:
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  Seed
(180)
Full
(3655)
Representative proteomes NCBI
(3093)
Meta
(363)
RP15
(399)
RP35
(770)
RP55
(1013)
RP75
(1223)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

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Pfam alignments:

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Curation and family details

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Seed source: Sarah Teichmann
Previous IDs: none
Type: Domain
Author: Finn RD, Bateman A
Number in seed: 180
Number in full: 3655
Average length of the domain: 180.30 aa
Average identity of full alignment: 37 %
Average coverage of the sequence by the domain: 42.15 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.4 20.4
Trusted cut-off 20.6 20.6
Noise cut-off 19.9 18.7
Model length: 182
Family (HMM) version: 12
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Species distribution

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Interactions

There are 2 interactions for this family. More...

Response_reg CheB_methylest

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the CheB_methylest domain has been found. There are 4 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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