3NRQ: Crystal Structure Of Copper-Reconstituted Fetp From Uropathogenic Escherichia Coli Strain F11

In the uropathogenic Escherichia coli strain F11, in silico genome analysis revealed the dicistronic iron uptake operon fetMP, which is under iron-regulated control mediated by the Fur regulator. The expression of fetMP in a mutant strain lacking known iron uptake systems improved growth under iron depletion and increased cellular iron accumulation. FetM is a member of the iron/lead transporter superfamily and is essential for iron uptake by the Fet system. FetP is a periplasmic protein that enhanced iron uptake by FetM. Recombinant FetP bound Cu(II) and the iron analog Mn(II) at distinct sites. The crystal structure of the FetP dimer reveals a copper site in each FetP subunit that adopts two conformations: CuA with a tetrahedral geometry composed of His(44), Met(90), His(97), and His(127), and CuB, a second degenerate octahedral geometry with the addition of Glu(46). The copper ions of each site occupy distinct positions and are separated by approximately 1.3 A. Nearby, a putative additional Cu(I) binding site is proposed as an electron source that may function with CuA/CuB displacement to reduce Fe(III) for transport by FetM. Together, these data indicate that FetMP is an additional iron uptake system composed of a putative iron permease and an iron-scavenging and potentially iron-reducing periplasmic protein.
PDB ID: 3NRQDownload
MMDB ID: 90614
PDB Deposition Date: 2010/6/30
Updated in MMDB: 2011/08
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 3NRQ: dimeric; determined by author and by software (PISA)
Molecular Components in 3NRQ
Label Count Molecule
Proteins (2 molecules)
Periplasmic Protein-probably Involved in High-affinity Fe2+ Transport
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB