PDBsum entry 4jj0

Electron transport

PDB id: 4jj0

Contents

Protein chains

181 a.a.

Ligands

HEC ×4

GOL

Waters ×336

PDB id:

4jj0

Name:

Electron transport

Title:

Crystal structure of mamp

Structure:

Mamp. Chain: a, b. Fragment: unp residues 26-268. Engineered: yes

Source:

Magnetococcus. Organism_taxid: 156889. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.80Å R-factor: 0.183 R-free: 0.239

Authors:

M.Siponen,D.Pignol,P.Arnoux

Key ref:

M.I.Siponen et al. (2013). Structural insight into magnetochrome-mediated magnetite biomineralization. Nature, 502, 681-684. PubMed id: 24097349 DOI: 10.1038/nature12573

Date:

07-Mar-13 Release date: 09-Oct-13

Protein chains

A0L9W2  (A0L9W2_MAGMM) -  PDZ/DHR/GLGF domain protein from Magnetococcus marinus (strain ATCC BAA-1437 / JCM 17883 / MC-1)

Seq: 261 a.a.

Struc: 181 a.a.*

* PDB and UniProt seqs differ at 19 residue positions (black crosses)

DOI no: 10.1038/nature12573

Nature 502:681-684 (2013)

PubMed id: 24097349

Structural insight into magnetochrome-mediated magnetite biomineralization.

M.I.Siponen, P.Legrand, M.Widdrat, S.R.Jones, W.J.Zhang, M.C.Chang, D.Faivre, P.Arnoux, D.Pignol.

ABSTRACT

Magnetotactic bacteria align along the Earth's magnetic field using an organelle called the magnetosome, a biomineralized magnetite (Fe(II)Fe(III)2O4) or greigite (Fe(II)Fe(III)2S4) crystal embedded in a lipid vesicle. Although the need for both iron(II) and iron(III) is clear, little is known about the biological mechanisms controlling their ratio. Here we present the structure of the magnetosome-associated protein MamP and find that it is built on a unique arrangement of a self-plugged PDZ domain fused to two magnetochrome domains, defining a new class of c-type cytochrome exclusively found in magnetotactic bacteria. Mutational analysis, enzyme kinetics, co-crystallization with iron(II) and an in vitro MamP-assisted magnetite production assay establish MamP as an iron oxidase that contributes to the formation of iron(III) ferrihydrite eventually required for magnetite crystal growth in vivo. These results demonstrate the molecular mechanisms of iron management taking place inside the magnetosome and highlight the role of magnetochrome in iron biomineralization.