PROSITE documentation PDOC00784
PTR2 family proton/oligopeptide symporters signatures


A family of eukaryotic and prokaryotic proteins that seem to be mainly involved in the intake of small peptides with the concomitant uptake of a proton has been recently characterized [1,2]. Proteins that belong to this family are:

  • Fungal peptide transporter PTR2.
  • Mammalian intestine proton-dependent oligopeptide transporter PeptT1.
  • Mammalian kidney proton-dependent oligopeptide transporter PeptT2.
  • Drosophila opt1.
  • Arabidopsis thaliana peptide transporters PTR2-A and PTR2-B (also known as the histidine transporting protein NTR1).
  • Arabidopsis thaliana proton-dependent nitrate/chlorate transporter CHL1.
  • Lactococcus proton-dependent di- and tri-peptide transporter dtpT.
  • Caenorhabditis elegans hypothetical protein C06G8.2.
  • Caenorhabditis elegans hypothetical protein F56F4.5.
  • Caenorhabditis elegans hypothetical protein K04E7.2.
  • Escherichia coli hypothetical protein ybgH.
  • Escherichia coli hypothetical protein ydgR.
  • Escherichia coli hypothetical protein yhiP.
  • Escherichia coli hypothetical protein yjdL.
  • Bacillus subtilis hypothetical protein yclF.

These integral membrane proteins are predicted to comprise twelve transmembrane regions. As signature patterns, we selected two of the best conserved regions. The first is a region that includes the end of the second transmembrane region, a cytoplasmic loop as well as the third transmembrane region. The second pattern corresponds to the core of the fifth transmembrane region.

Expert(s) to contact by email:

Steiner H.-Y.
Becker J.M.

Last update:

November 1997 / Patterns and text revised.


Technical section

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

PTR2_1, PS01022; PTR2 family proton/oligopeptide symporters signature 1  (PATTERN)

PTR2_2, PS01023; PTR2 family proton/oligopeptide symporters signature 2  (PATTERN)


1AuthorsPaulsen I.T. Skurray R.A.
TitleThe POT family of transport proteins.
SourceTrends Biochem. Sci. 19:404-404(1994).
PubMed ID7817396

2AuthorsSteiner H.-Y. Naider F. Becker J.M.
TitleThe PTR family: a new group of peptide transporters.
SourceMol. Microbiol. 16:825-834(1995).
PubMed ID7476181

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