PROSITE documentation PDOC51779
POTRA domain profile


The polypeptide-transport-associated (POTRA) domain is a module found in members of the FtsQ/DivIB, ShlB, CGI51 (with one repeat), Toc75, YTFM (with three repeats) and D15 (with five repeats) protein families. The POTRA domains are hypothesized to mediate protein-protein interactions, nucleate β-strands formation in nascent outer membrane proteins (OMPs) and have chaperone-like activity [1,2,3,4,5].

The POTRA domain fold comprises a three-stranded β-sheet overlaid with a pair of antiparallel helices. The order of secondary-structure elements is β-α-α-β-β; the first and second β strands form the two edges of the sheet, with the β3 strand sandwiched between them (see <PDB:4QKY>). The conserved residues that define the POTRA domains are primarily in the hydrophobic core or loop regions, suggesting that they are important for the structural integrity of POTRA domain [2,3,4,5].

Some proteins known to contain a POTRA domain are listed below:

  • Escherichia coli outer membrane protein assembly factor BamA, involved in assembly and insertion of β-barrel proteins into the outer membrane.
  • Escherichia coli cell division protein FtsQ.
  • Bacillus subtilis cell division protein DivIB.
  • Serratia marcescens hemolysin transporter protein ShlB, a virulence-factor transporter that is present in the outer membrane.
  • Arabidopsis thaliana chloroplastic protein TOC75, mediates the insertion of proteins targeted to the outer membrane of chloroplasts.
  • Human sorting and assembly machinery component 50 (SAM50), plays a crucial role in the maintenance of the structure of mitochondrial cristae and the proper assembly of the mitochondrial respiratory chain complexes.

The profile we developed covers the entire POTRA domain.

Last update:

October 2015 / First entry.


Technical section

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

POTRA, PS51779; POTRA domain profile  (MATRIX)


1AuthorsSanchez-Pulido L. Devos D. Genevrois S. Vicente M. Valencia A.
TitlePOTRA: a conserved domain in the FtsQ family and a class of beta-barrel outer membrane proteins.
SourceTrends Biochem. Sci. 28:523-526(2003).
PubMed ID14559180

2AuthorsKim S. Malinverni J.C. Sliz P. Silhavy T.J. Harrison S.C. Kahne D.
TitleStructure and function of an essential component of the outer membrane protein assembly machine.
SourceScience 317:961-964(2007).
PubMed ID17702946

3AuthorsGatzeva-Topalova P.Z. Walton T.A. Sousa M.C.
TitleCrystal structure of YaeT: conformational flexibility and substrate recognition.
SourceStructure 16:1873-1881(2008).
PubMed ID19081063

4Authorsvan den Ent F. Vinkenvleugel T.M.F. Ind A. West P. Veprintsev D. Nanninga N. den Blaauwen T. Loewe J.
TitleStructural and mutational analysis of the cell division protein FtsQ.
SourceMol. Microbiol. 68:110-123(2008).
PubMed ID18312270

5AuthorsGatzeva-Topalova P.Z. Warner L.R. Pardi A. Sousa M.C.
TitleStructure and flexibility of the complete periplasmic domain of BamA: the protein insertion machine of the outer membrane.
SourceStructure 18:1492-1501(2010).
PubMed ID21070948

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