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	PROSITE documentation PDOC00465 [for PROSITE entry PS50111]

Bacterial chemotaxis sensory transducers signature and profile

Bacterial chemotactic-signal transducers [1,2] are proteins that respond to changes in the concentration of attractants and repellents in the environment, and transduce a signal from the outside to the inside of the cell. These proteins undergo two covalent modifications: deamidation and reversible methylation. 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.

In Escherichia coli and related bacteria, there are four different chemotactic transducers:

• tsr, responsible for taxis to the attractants L-serine and related amino acids and away from the repellents leucine, indole, and weak acids.
• tar, responsible for taxis to the attractants L-aspartate and related amino and dicarboxylic acids. Also mediates taxis to the attractant maltose via an interaction with the periplasmic maltose-binding protein. Mediates taxis away from the repellents cobalt and nickel.
• trg, responsible for taxis to ribose and galactose via an interaction with the periplasmic ribose- or galactose-binding proteins.
• tap, responsible for taxis towards dipeptides via an interaction with the periplasmic dipeptide-binding protein.

In Enterobacter aerogenes [3] there are at least two different chemotactic transducers:

• tsr, responsible for taxis to the attractant L-serine.
• tas, responsible for taxis to the attractant L-aspartate.

In Salmonella typhimurium [4], in addition to tar, there is:

• tcp, responsible for taxis to the attractant citrate.

All these proteins are composed of the same structural domains: a N-terminal region that resembles a signal peptide, but which is not removed from the mature protein and serves as a membrane-spanning region; a periplasmic domain of about 160 amino acids that forms the receptor domain; a second transmembrane region and finally a C-terminal cytoplasmic domain of about 300 amino acids which contains the methylation sites.

The methyl-accepting sites are specific glutamate residues (some of these sites are translated as glutamine but are irreversibly deamidated by cheB). They are clustered in two regions of the cytoplasmic domain [5]. As a signature pattern we have selected the first of these two regions.

Last update:

September 2002 / text revised; profile added.

PROSITE methods (with tools and information) covered by this documentation:

CHEMOTAXIS_TRANSDUC_2, PS50111; Bacterial chemotaxis sensory transducers domain profile  (MATRIX)

• Sequences in UniProtKB/Swiss-Prot known to belong to this class: 78
  • detected by PS50111: 78 (true positives)
  • undetected by PS50111: 0 (false negative or 'partial')
• Other sequence(s) in UniProtKB/Swiss-Prot detected by PS50111:
  1 false positive.
• Domain architecture view of Swiss-Prot proteins matching PS50111
  
• Retrieve an alignment of UniProtKB/Swiss-Prot true positive hits:
  Clustal format, color, condensed view  /  Clustal format, color  /  Clustal format, plain text  /  Fasta format
• Retrieve the sequence logo from the alignment
• Taxonomic distribution of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS50111
• Retrieve a list of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS50111
• Scan UniProtKB (Swiss-Prot and/or TrEMBL) entries against PS50111
• View ligand binding statistics of PS50111
• Matching PDB structures: 1QU7 2CH7 3JA6 3ZX6 [ALL]

CHEMOTAXIS_TRANSDUC_1, PS00538; Bacterial chemotaxis sensory transducers signature  (PATTERN)

• Consensus pattern:
  R-T-E-[EQ]-Q-x(2)-[SA]-[LIVM]-x-[EQ]-T-A-A-S-M-E-Q-L-T-A-T-V
  The two E/Q position and the last Q are all sites of reversible methylation
• Sequences in UniProtKB/Swiss-Prot known to belong to this class: 57
  • detected by PS00538: 8 (true positives)
  • undetected by PS00538: 49 (49 false negatives and 0 'partial')
• Other sequence(s) in UniProtKB/Swiss-Prot detected by PS00538:
  NONE.
• Retrieve an alignment of UniProtKB/Swiss-Prot true positive hits:
  Clustal format, color, condensed view  /  Clustal format, color  /  Clustal format, plain text  /  Fasta format
• Retrieve the sequence logo from the alignment
• Taxonomic distribution of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS00538
• Retrieve a list of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS00538
• Scan UniProtKB (Swiss-Prot and/or TrEMBL) entries against PS00538
• View ligand binding statistics of PS00538
• Matching PDB structures: 1QU7 3ZX6 [ALL]

1	Authors	Stewart R.C., Dahlquist F.W.
	Source	Chem. Rev. 87:997-1025(1987).

2	Authors	Hazelbauer G.L.
	Title	The bacterial chemosensory system.
	Source	Can. J. Microbiol. 34:466-474(1988).
	PubMed ID	3052756

3	Authors	Dahl M.K., Boos W., Manson M.D.
	Title	Evolution of chemotactic-signal transducers in enteric bacteria.
	Source	J. Bacteriol. 171:2361-2371(1989).
	PubMed ID	2496104

4	Authors	Yamamoto K., Imae Y.
	Title	Cloning and characterization of the Salmonella typhimurium-specific chemoreceptor Tcp for taxis to citrate and from phenol.
	Source	Proc. Natl. Acad. Sci. U.S.A. 90:217-221(1993).
	PubMed ID	8419927

5	Authors	Rice M.S., Dahlquist F.W.
	Title	Sites of deamidation and methylation in Tsr, a bacterial chemotaxis sensory transducer.
	Source	J. Biol. Chem. 266:9746-9753(1991).
	PubMed ID	2033064

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