PDBsum entry 6bpm

Membrane protein

PDB id: 6bpm

Contents

Protein chains

711 a.a.

Ligands

POG ×6

BOG ×2

Waters ×201

PDB id:

6bpm

Name:

Membrane protein

Title:

The crystal structure of the ferric-catecholate import receptor fiu from k12 e. Coli: closed form (c21)

Structure:

Catecholate siderophore receptor fiu. Chain: c, a. Synonym: ferric iron uptake protein,tonb-dependent receptor fiu. Engineered: yes

Source:

Escherichia coli (strain k12). Organism_taxid: 83333. Strain: k12. Gene: fiu, ybil, b0805, jw0790. Expressed in: escherichia coli. Expression_system_taxid: 511693.

Resolution:

2.50Å R-factor: 0.202 R-free: 0.259

Authors:

R.Grinter

Key ref:

R.Grinter and T.Lithgow (2019). The structure of the bacterial iron-catecholate transporter Fiu suggests that it imports substrates via a two-step mechanism. J Biol Chem, 294, 19523-19534. PubMed id: 31712312 DOI: 10.1074/jbc.RA119.011018

Date:

23-Nov-17 Release date: 28-Nov-18

Protein chains

P75780  (FIU_ECOLI) -  Catecholate siderophore receptor Fiu from Escherichia coli (strain K12)

Seq: 760 a.a.

Struc: 711 a.a.

DOI no: 10.1074/jbc.RA119.011018

J Biol Chem 294:19523-19534 (2019)

PubMed id: 31712312

The structure of the bacterial iron-catecholate transporter Fiu suggests that it imports substrates via a two-step mechanism.

R.Grinter, T.Lithgow.

ABSTRACT

The ferric iron uptake (Fiu) transporter from Escherichia coli functions in the transport of iron-catecholate complexes across the bacterial outer membrane, providing the bacterium with iron, which is essential for growth. Recently it has become clear that Fiu also represents a liability for E. coli because its activity allows import of antimicrobial compounds that mimic catecholate. This inadvertent import suggests the potential utility of antimicrobial catechol siderophore mimetics in managing bacterial infections. However, to fully exploit these compounds, a detailed understanding of the mechanism of transport through Fiu and related transporters is required. To address this question, we determined the crystal structure of Fiu at 2.1-2.9 Å and analyzed its function in E. coli Through analysis of the Fiuo crystal structure, in combination with in silico docking and mutagenesis, we provide insight into how Fiu and related transporters bind catecholate in a surface-exposed cavity. Moreover, through determination of the structure of Fiu in multiple crystal states, we revealed the presence of a large, selectively gated cavity in the interior of this transporter. This chamber is large enough to accommodate the Fiu substrate and may allow import of substrates via a two-step mechanism. This would avoid channel formation through the transporter and inadvertent import of toxic molecules. As Fiu and its homologs are the targets of substrate-mimicking antibiotics, these results may assist in the development of these compounds.