STN

Secretin and TonB N terminus short domain
STN
SMART accession number:SM00965
Description: This is a short domain found at the N-terminus of the Secretins of the bacterial type II/III secretory system as well as the TonB-dependent receptor proteins. These proteins are involved in TonB-dependent active uptake of selective substrates.
Interpro abstract (IPR011662):

This is a conserved region found at the N-terminal region of bacterial proteins involved in either protein secretion or the uptake of selective substrates, including:

  • Bundle-forming pilus protein B, an outer-membrane protein absolutely required for pilus biogenesis, and for enteropathogenic Escherichia coli localized adherence and autoaggregation [(PUBMED:8932312)].
  • PilQ, which is required for type IV pilus biogenesis and competence and is thought to function both as a pore for exit of the pilus and as a channel for entry of haem and antimicrobial agents and uptake of transforming DNA [(PUBMED:14729699)].
  • PupB, a specific receptor for the siderophores ferric pseudobactin BN8 and ferric pseudobactin BN7, iron chelating molecules that allow the organism to extract iron from the environment, especially under iron-restricted conditions [(PUBMED:8392140)].
  • TonB, which couples the electrochemical potential of the cytoplasmic membrane to the active transport of iron-siderophores and vitamin B12 across the outer membrane [(PUBMED:15802653)].

GO component:outer membrane (GO:0019867)
Family alignment:
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There are 2087 STN domains in 2068 proteins in SMART's nrdb database.

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