PDBsum entry 4am5

Metal binding protein

PDB id: 4am5

Contents

Protein chains

159 a.a.

Ligands

HEM

Metals

_FE ×4

Waters ×324

PDB id:

4am5

Name:

Metal binding protein

Title:

Bacterioferritin from blastochloris viridis

Structure:

Bacterioferritin. Chain: a, b

Source:

Blastochloris viridis. Organism_taxid: 1079

Resolution:

1.58Å R-factor: 0.157 R-free: 0.174

Authors:

W.Y.Wahlgren,H.Omran,D.Von Stetten,A.Royant,S.Van Der Post,G.Katona

Key ref:

W.Y.Wahlgren et al. (2012). Structural characterization of bacterioferritin from Blastochloris viridis. Plos One, 7, e46992. PubMed id: 23056552

Date:

07-Mar-12 Release date: 31-Oct-12

Protein chains

K7N5M0  (K7N5M0_BLAVI) -  Bacterioferritin from Blastochloris viridis

Seq: 159 a.a.

Struc: 159 a.a.

Enzyme reactions

• Enzyme class: E.C.1.16.3.1 - ferroxidase.
• Reaction: 4 Fe²⁺ + O2 + 4 H⁺ = 4 Fe³⁺ + 2 H2O
• Cofactor: Cu cation

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Key reference

Plos One 7:e46992 (2012)

PubMed id: 23056552

Structural characterization of bacterioferritin from Blastochloris viridis.

W.Y.Wahlgren, H.Omran, D.von Stetten, A.Royant, S.van der Post, G.Katona.

ABSTRACT

Iron storage and elimination of toxic ferrous iron are the responsibility of bacterioferritins in bacterial species. Bacterioferritins are capable of oxidizing iron using molecular oxygen and import iron ions into the large central cavity of the protein, where they are stored in a mineralized form. We isolated, crystallized bacterioferritin from the microaerophilic/anaerobic, purple non-sulfur bacterium Blastochloris viridis and determined its amino acid sequence and X-ray structure. The structure and sequence revealed similarity to other purple bacterial species with substantial differences in the pore regions. Static 3- and 4-fold pores do not allow the passage of iron ions even though structural dynamics may assist the iron gating. On the other hand the B-pore is open to water and larger ions in its native state. In order to study the mechanism of iron import, multiple soaking experiments were performed. Upon Fe(II) and urea treatment the ferroxidase site undergoes reorganization as seen in bacterioferritin from Escherichia coli and Pseudomonas aeruginosa. When soaking with Fe(II) only, a closely bound small molecular ligand is observed close to Fe(1) and the coordination of Glu94 to Fe(2) changes from bidentate to monodentate. DFT calculations indicate that the bound ligand is most likely a water or a hydroxide molecule representing a product complex. On the other hand the different soaking treatments did not modify the conformation of other pore regions.