Homoserine/threonine resistance transporter

Homoserine lactone efflux protein
Identifiers
Symbol RhtB
Pfam PF01810
InterPro IPR004778.

The resistance to homoserine/threonine (RhtB) family (TC# 2.A.76) belongs to the lysine exporter (LysE) superfamily of transporters.[1] Hundreds of sequenced proteins, derived from Gram-negative and Gram-positive bacteria as well as archaea, comprise the RhtB family, but few of these proteins are functionally characterized.[2]

Members

The first two members of the RhtB family to be characterized functionally were the RhtB (TC# 2.A.76.1.1) and RhtC (TC# 2.A.76.1.2) permeases of E. coli.[3][4]

E. coli possesses five paralogues, and a large region of one of them (YahN of E. coli; TC# 2.A.76.1.3) exhibits significant sequence similarity to YggA of E. coli (TC# 2.A.75.1.2), an established member of the LysE family (TC #2.A.75).

The PSI-BLAST program groups the LysE family (TC# 2.A.75), the RhtB family and the CadD family (TC #2.A.77) together. These proteins are all of about the same size and apparent topology, further suggesting a common evolutionary origin.[2]

The leucine exporter homologue (YeaS or LeuE; TC# 2.A.76.1.5) exports leucine and several other neutral, hydrophobic amino acids.[5]

A representative list of proteins belonging to the RhtB family can be found in the Transporter Classification Database.

General transport reaction

The transport reaction presumably catalyzed by members of the RhtB family is:[6]

amino acid (in) + nH+ (out) ⇌ amino acid (out) + nH+ (in)

See also

References

  1. Tsu, Brian V.; Saier, Milton H. (2015-01-01). "The LysE Superfamily of Transport Proteins Involved in Cell Physiology and Pathogenesis". PloS One. 10 (10): e0137184. doi:10.1371/journal.pone.0137184. ISSN 1932-6203. PMC 4608589Freely accessible. PMID 26474485.
  2. 1 2 Vrljic, M.; Garg, J.; Bellmann, A.; Wachi, S.; Freudl, R.; Malecki, M. J.; Sahm, H.; Kozina, V. J.; Eggeling, L. (1999-11-01). "The LysE superfamily: topology of the lysine exporter LysE of Corynebacterium glutamicum, a paradyme for a novel superfamily of transmembrane solute translocators". Journal of Molecular Microbiology and Biotechnology. 1 (2): 327–336. ISSN 1464-1801. PMID 10943564.
  3. Aleshin, V. V.; Zakataeva, N. P.; Livshits, V. A. (1999-04-01). "A new family of amino-acid-efflux proteins". Trends in Biochemical Sciences. 24 (4): 133–135. doi:10.1016/s0968-0004(99)01367-5. ISSN 0968-0004. PMID 10322417.
  4. Zakataeva, N. P.; Aleshin, V. V.; Tokmakova, I. L.; Troshin, P. V.; Livshits, V. A. (1999-06-11). "The novel transmembrane Escherichia coli proteins involved in the amino acid efflux". FEBS letters. 452 (3): 228–232. doi:10.1016/s0014-5793(99)00625-0. ISSN 0014-5793. PMID 10386596.
  5. Kutukova, Ekaterina A.; Livshits, Vitaliy A.; Altman, Irina P.; Ptitsyn, Leonid R.; Zyiatdinov, Michael H.; Tokmakova, Irina L.; Zakataeva, Natalia P. (2005-08-29). "The yeaS (leuE) gene of Escherichia coli encodes an exporter of leucine, and the Lrp protein regulates its expression". FEBS letters. 579 (21): 4629–4634. doi:10.1016/j.febslet.2005.07.031. ISSN 0014-5793. PMID 16098526.
  6. "TCDB » SEARCH". www.tcdb.org. Retrieved 2016-02-25.


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