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- **********************************************
- * TonB-dependent receptor proteins signature *
- **********************************************
-
- In Escherichia coli the tonB protein interacts with outer membrane receptor
- proteins that carry out high-affinity binding and energy-dependent uptake of
- specific substrates into the periplasmic space. These substrates are either
- poorly permeable through the porin channels or are encountered at very low
- concentrations. In the absence of tonB these receptors bind their substrates
- but do not carry out active transport. The tonB protein also interacts with
- some colicins. The proteins that are currently known to interact with tonB
- are:
-
- Gene Function or name
- ---- -------------------------------------------------------------------
- btuB Receptor for cobalamin.
- cir Receptor for colicin I (exact substrate not known).
- fecA Receptor for iron dicitrate.
- fepA Receptor for ferric enterochelin.
- fhuA Receptor for ferrichrome-iron.
- fhuE Receptor for ferric coprogen, ferrioxamine B, and rhodotrulic acid.
- foxA Receptor for ferrioxamine (Yersinia enterocolitica).
- hemR Receptor for hemin (Yersinia enterocolitica).
- irgA Receptor for ferric vibriobactin (Vibrio cholerae).
- iutA Receptor for ferric aerobactin.
- pfeA Receptor for ferric enterobactin (Pseudomonas aeruginosa).
- pupA Receptor for ferric pseudobactin 358 (Pseudomonas putida).
- tbp1 Receptor for transferrin (Neisseria gonorrhoeae).
-
- cba Colicin B, a channel forming colicin.
- cda Colicin D.
- cma Colicin M, inhibitor of murein biosynthesis.
-
- All these proteins contain, at their N-terminus, a short conserved region [1,
- 2,3], called the tonB-box, involved in the interaction of the protein with the
- tonB protein [4].
-
- -Consensus pattern: <x(10,60)-[DEF]-T-[LIVMF]-[LIVSTEQ]-V-x-[AGP]-[STANPK]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for cda, pfeA and pupA.
- -Other sequence(s) detected in SWISS-PROT: 12.
- -Last update: June 1994 / Text revised.
-
- [ 1] Lundrigan M.D., Kadner R.J.
- J. Biol. Chem. 261:10797-10801(1986).
- [ 2] Schramm E., Mende J., Braun V., Kamp R.M.
- J. Bacteriol. 169:3350-3357(1987).
- [ 3] Nau C.D., Konisky J.
- J. Bacteriol. 171:1041-1047(1989).
- [ 4] Gudmundsdottir A., Bell P.E., Lundrigan M.D., Bradbeer C., Kadner R.J.
- J. Bacteriol. 171:6526-6533(1989).
-