This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1xkw
From Proteopedia
Pyochelin outer membrane receptor FptA from Pseudomonas aeruginosa
Overview
Pyochelin is a siderophore and virulence factor common to Burkholderia cepacia and several Pseudomonas strains. We describe at 2.0 A resolution the crystal structure of the pyochelin outer membrane receptor FptA bound to the iron-pyochelin isolated from Pseudomonas aeruginosa. One pyochelin molecule bound to iron is found in the protein structure, providing the first three-dimensional structure at the atomic level of this siderophore. The pyochelin molecule provides a tetra-dentate coordination of iron, while the remaining bi-dentate coordination is ensured by another molecule not specifically recognized by the protein. The overall structure of the pyochelin receptor is typical of the TonB-dependent transporter superfamily, which uses the proton motive force from the cytoplasmic membrane through the TonB-ExbB-ExbD energy transducing complex to transport ferric ions across the bacterial outer membrane: a transmembrane 22 beta-stranded barrel occluded by a N-terminal domain that contains a mixed four-stranded beta-sheet. The N-terminal TonB box is disordered in two crystal forms, and loop L8 is found to point towards the iron-pyochelin complex, suggesting that the receptor is in a transport-competent conformation.
About this Structure
1XKW is a Single protein structure of sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA.
Reference
Crystal structure at high resolution of ferric-pyochelin and its membrane receptor FptA from Pseudomonas aeruginosa., Cobessi D, Celia H, Pattus F, J Mol Biol. 2005 Sep 30;352(4):893-904. PMID:16139844 Page seeded by OCA on Sat May 3 15:09:49 2008
