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14  structures 7811  species 3  interactions 84952  sequences 455  architectures

Family: MCPsignal (PF00015)

Summary: Methyl-accepting chemotaxis protein (MCP) signalling domain

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This is the Wikipedia entry entitled "Methyl-accepting chemotaxis protein". More...

Methyl-accepting chemotaxis protein Edit Wikipedia article

MCPsignal
3zx6.png
Methyl-accepting chemotaxis protein I. PDB entry 3zx6[1]
Identifiers
Symbol MCPsignal
Pfam PF00015
Pfam clan CL0510
InterPro IPR004089
PROSITE PDOC00465
SCOP 1qu7
SUPERFAMILY 1qu7

Methyl-accepting chemotaxis protein (MCP) is a transmembrane sensor protein of bacteria. Use of the MCP allows bacteria to detect concentrations of molecules in the extracellular matrix so that the bacteria may smooth swim or tumble accordingly. If the bacteria detects rising levels of attractants (nutrients) or declining levels of repellents (toxins), the bacteria will continue swimming forward, or smooth swimming. If the bacteria detects declining levels of attractants or rising levels of repellents, the bacteria will tumble and re-orient itself in a new direction. In this manner, a bacteria may swim towards nutrients and away from toxins[2]

Environmental diversity gives rise to diversity in bacterial signalling receptors, and consequently there are many genes encoding MCPs.[3] For example, there are four well-characterised MCPs found in Escherichia coli: Tar (taxis towards aspartate and maltose, away from nickel and cobalt), Tsr (taxis towards serine, away from leucine, indole and weak acids), Trg (taxis towards galactose and ribose) and Tap (taxis towards dipeptides).

Structure

MCPs share similar structure and signalling mechanism. MCPs form dimers. Three dimers of MCP spontaneously form trimers. Trimers are complexed by CheA and CheW into hexagonal lattices. MCPs either bind ligands directly or interact with ligand-binding proteins, transducing the signal to downstream signalling proteins in the cytoplasm. Most MCPs contain: (a) an N-terminal signal peptide that is a transmembrane alpha-helix in the mature protein; (b) a poorly-conserved periplasmic receptor (ligand-binding) domain; (c) a transmembrane alpha-helix; (d) generally one or more HAMP domains and (e) a highly-conserved C-terminal cytoplasmic domain that interacts with downstream signalling components. The C-terminal domain contains the methylated glutamate residues.

MCPs undergo two covalent modifications: deamidation and reversible methylation at a number of glutamate residues. Attractants increase the level of methylation, while repellents decrease it. The methyl groups are added by the methyl-transferase CheR and are removed by the methylesterase CheB.

Function

Binding a ligand causes a conformational change in the MCP receptor which translates down the hairpin structure. At the tip of the hairpin are two proteins that associate to the MCP: CheW and CheA. CheA acts as the sensor kinase. CheA has kinase activity and autophosphorylates itself on a histidyl residue when activated by the MCP. CheW is believed to be a transducer of the signal from the MCP to CheA [ref?]. Activated CheA transfers its phosphoryl group to CheY, a response regulator. Phosphorylated CheY phosphorylates the basal body FliM which is connected to the flagellum. Phosphorylation of the basal body acts as a flagellar switch and changes the direction of rotation of the flagellum. This change in direction allows for alternation between smooth swimming and tumbling which biases the bacterial random walk towards attractant.

References

  1. ^ Ferris, H. U.; Zeth, K.; Hulko, M.; Dunin-Horkawicz, S.; Lupas, A. N. (2014). "Axial helix rotation as a mechanism for signal regulation inferred from the crystallographic analysis of the E. Coli serine chemoreceptor". Journal of Structural Biology. doi:10.1016/j.jsb.2014.03.015.  edit
  2. ^ Derr P, Boder E, Goulian M (February 2006). "Changing the specificity of a bacterial chemoreceptor". J. Mol. Biol. 355 (5): 923–32. doi:10.1016/j.jmb.2005.11.025. PMID 16359703. 
  3. ^ Alexander RP, Zhulin IB (February 2007). "Evolutionary genomics reveals conserved structural determinants of signaling and adaptation in microbial chemoreceptors". Proc. Natl. Acad. Sci. U.S.A. 104 (8): 2885–90. doi:10.1073/pnas.0609359104. PMC 1797150. PMID 17299051. 

External links

This article incorporates text from the public domain Pfam and InterPro IPR004089

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Methyl-accepting chemotaxis protein (MCP) signalling domain Provide feedback

This domain is thought to transduce the signal to CheA since it is highly conserved in very diverse MCPs.

Literature references

  1. Hanlon DW, Marquez-Magana LM, Carpenter PB, Chamberlin MJ, Ordal GW; , J Biol Chem 1992;267:12055-12060.: Sequence and characterization of Bacillus subtilis CheW. PUBMED:1601874 EPMC:1601874


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR004089

Methyl-accepting chemotaxis proteins (MCPs) are a family of bacterial receptors that mediate chemotaxis to diverse signals, responding to changes in the concentration of attractants and repellents in the environment by altering swimming behaviour [PUBMED:16359703]. Environmental diversity gives rise to diversity in bacterial signalling receptors, and consequently there are many genes encoding MCPs [PUBMED:17299051]. For example, there are four well-characterised MCPs found in Escherichia coli: Tar (taxis towards aspartate and maltose, away from nickel and cobalt), Tsr (taxis towards serine, away from leucine, indole and weak acids), Trg (taxis towards galactose and ribose) and Tap (taxis towards dipeptides).

MCPs share similar topology and signalling mechanisms. MCPs either bind ligands directly or interact with ligand-binding proteins, transducing the signal to downstream signalling proteins in the cytoplasm. MCPs undergo two covalent modifications: deamidation and reversible methylation at a number of glutamate residues. Attractants increase the level of methylation, while repellents decrease it. The methyl groups are added by the methyl-transferase cheR and are removed by the methylesterase cheB. Most MCPs are homodimers that contain the following organisation: an N-terminal signal sequence that acts as a transmembrane domain in the mature protein; a poorly-conserved periplasmic receptor (ligand-binding) domain; a second transmembrane domain; and a highly-conserved C-terminal cytoplasmic domain that interacts with downstream signalling components. The C-terminal domain contains the glycosylated glutamate residues.

This entry represents the signalling domain found in several methyl-accepting chemotaxis proteins. This domain is thought to transduce the signal to CheA since it is highly conserved in very diverse MCPs.

Gene Ontology

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Domain organisation

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Alignments

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  Seed
(9)
Full
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Representative proteomes NCBI
(75383)
Meta
(1321)
RP15
(2292)
RP35
(6256)
RP55
(9704)
RP75
(13546)
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  Seed
(9)
Full
(84952)
Representative proteomes NCBI
(75383)
Meta
(1321)
RP15
(2292)
RP35
(6256)
RP55
(9704)
RP75
(13546)
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Curation and family details

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Seed source: Blast MCP1_ECOLI/361-421
Previous IDs: none
Type: Family
Author: Sonnhammer ELL
Number in seed: 9
Number in full: 84952
Average length of the domain: 194.30 aa
Average identity of full alignment: 33 %
Average coverage of the sequence by the domain: 35.73 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 30.0 30.0
Trusted cut-off 30.0 30.0
Noise cut-off 29.9 29.9
Model length: 207
Family (HMM) version: 17
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Species distribution

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Archea Archea Eukaryota Eukaryota
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Interactions

There are 3 interactions for this family. More...

CheW HAMP MCPsignal

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 MCPsignal domain has been found. There are 14 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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