|Gene:||cheR||Accession Numbers: EG10148 (MetaCyc), b1884, ECK1885|
Species: Escherichia coli K-12 substr. MG1655
CheR is a component of the adaptation pathway of the chemotaxis sensory transduction system of Escherichia coli. Adaptation allows the cell to adapt to a background stimulus so that it is capable of recognizing a concentration gradient even in the presence of a large constant level of attractant or repellent [Falke97]. A feedback loop works to control adaptation by covalently modifying a number of glutamate residues on the cytoplasmic portion of the methylatable chemotaxis protein (MCP) receptor. CheR is a methlytransferase which is transiently bound to the C terminus of the MCP receptor where it methyl esterifies the glutamate side chains, increasing the kinase activation signal of the receptor. The activity of CheR is counteracted by the methylesterase CheB, which , when phosphorylated becomes activated and hydrolyzes the methyl esters, causing a feedback reduction in the receptor's kinase activity [Falke97].
Locations: inner membrane, cytosol
|Map Position: [1,966,528 <- 1,967,388]|
Molecular Weight of Polypeptide: 32.849 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0006286 , CGSC:926 , DIP:DIP-9273N , EchoBASE:EB0146 , EcoGene:EG10148 , EcoliWiki:b1884 , ModBase:P07364 , OU-Microarray:b1884 , PortEco:cheR , PR:PRO_000022279 , Protein Model Portal:P07364 , RefSeq:NP_416398 , RegulonDB:EG10148 , SMR:P07364 , String:511145.b1884 , Swiss-Model:P07364 , UniProt:P07364
Relationship Links: InterPro:IN-FAMILY:IPR000780 , InterPro:IN-FAMILY:IPR022641 , InterPro:IN-FAMILY:IPR022642 , InterPro:IN-FAMILY:IPR026024 , Pfam:IN-FAMILY:PF01739 , Pfam:IN-FAMILY:PF03705 , Prints:IN-FAMILY:PR00996 , Prosite:IN-FAMILY:PS50123 , Smart:IN-FAMILY:SM00138
|Biological Process:||GO:0006479 - protein methylation
GO:0006935 - chemotaxis [UniProtGOA11a]
GO:0032259 - methylation [UniProtGOA11a]
|Molecular Function:||GO:0008168 - methyltransferase activity
GO:0008757 - S-adenosylmethionine-dependent methyltransferase activity [GOA01a]
GO:0008983 - protein-glutamate O-methyltransferase activity [GOA01]
GO:0016740 - transferase activity [UniProtGOA11a]
|Cellular Component:||GO:0005829 - cytosol
GO:0005886 - plasma membrane [Ridgway77]
|MultiFun Terms:||cell processes → motility, chemotaxis, energytaxis (aerotaxis, redoxtaxis etc)|
|information transfer → protein related → posttranslational modification|
Enzymatic reaction of: chemotaxis protein methyltransferase
Synonyms: MCP O-methyltransferase, S-adenosyl-L-methionine:protein-L-glutamate O-methyltransferase, methyl-accepting chemotaxis protein O-methyltransferase, protein-glutamate O-methyltransferase
EC Number: 184.108.40.206
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
The reaction is physiologically favored in the direction shown.
Alternative Substrates [Comment 1]:
The methyl-accepting chemotaxis proteins (MCPs) mediate chemotaxis responses in E. coli. They are reversibly methyl esterified at specific glutamate residues. The cheR encoded methyltransferase transfers methyl groups from S-adenosylmethionine (AdoMet) to those glutamate residues. Increased levels of methylation result in tumbling behavior of the cell while decreased levels result in smooth swimming. [Neidhardt96, Russell89, Hoch95]
Primary Physiological Regulators of Enzyme Activity: S-adenosyl-L-homocysteine
|Conserved-Region||15 -> 286|
|Protein-Segment||212 -> 213|
|Protein-Segment||230 -> 231|
10/20/97 Gene b1884 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10148; confirmed by SwissProt match.
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Falke97: Falke JJ, Bass RB, Butler SL, Chervitz SA, Danielson MA (1997). "The two-component signaling pathway of bacterial chemotaxis: a molecular view of signal transduction by receptors, kinases, and adaptation enzymes." Annu Rev Cell Dev Biol 13;457-512. PMID: 9442881
Neidhardt96: Neidhardt FC, Curtiss III R, Ingraham JL, Lin ECC, Low Jr KB, Magasanik B, Reznikoff WS, Riley M, Schaechter M, Umbarger HE "Escherichia coli and Salmonella, Cellular and Molecular Biology, Second Edition." American Society for Microbiology, Washington, D.C., 1996.
Russell89: Russell CB, Stewart RC, Dahlquist FW (1989). "Control of transducer methylation levels in Escherichia coli: investigation of components essential for modulation of methylation and demethylation reactions." J Bacteriol 1989;171(7);3609-18. PMID: 2661528
Stock84: Stock JB, Clarke S, Koshland DE (1984). "The protein carboxylmethyltransferase involved in Escherichia coli and Salmonella typhimurium chemotaxis." Methods Enzymol 1984;106;310-21. PMID: 6387375
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