5MM3 image
Deposition Date 2016-12-08
Release Date 2017-10-25
Last Version Date 2024-01-17
Entry Detail
PDB ID:
5MM3
Title:
Unstructured MamC magnetite-binding protein located between two helices.
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.10 Å
R-Value Free:
0.22
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 41 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Sugar ABC transporter substrate-binding protein,Magnetosome protein MamC,Sugar ABC transporter substrate-binding protein
Chain IDs:A, B
Chain Length:412
Number of Molecules:2
Biological Source:Methanosarcina mazei, Magnetospirillum sp. XM-1
Primary Citation
The importance of the helical structure of a MamC-derived magnetite-interacting peptide for its function in magnetite formation.
Acta Crystallogr D Struct Biol 74 10 20 (2018)
PMID: 29372895 DOI: 10.1107/S2059798317017491

Abstact

Biomineralization is the process of mineral formation by organisms and involves the uptake of ions from the environment in order to produce minerals, with the process generally being mediated by proteins. Most proteins that are involved in mineral interactions are predicted to contain disordered regions containing large numbers of negatively charged amino acids. Magnetotactic bacteria, which are used as a model system for iron biomineralization, are Gram-negative bacteria that can navigate through geomagnetic fields using a specific organelle, the magnetosome. Each organelle comprises a membrane-enveloped magnetic nanoparticle, magnetite, the formation of which is controlled by a specific set of proteins. One of the most abundant of these proteins is MamC, a small magnetosome-associated integral membrane protein that contains two transmembrane α-helices connected by an ∼21-amino-acid peptide. In vitro studies of this MamC peptide showed that it forms a helical structure that can interact with the magnetite surface and affect the size and shape of the growing crystal. Our results show that a disordered structure of the MamC magnetite-interacting component (MamC-MIC) abolishes its interaction with magnetite particles. Moreover, the size and shape of magnetite crystals grown in in vitro magnetite-precipitation experiments in the presence of this disordered peptide were different from the traits of crystals grown in the presence of other peptides or in the presence of the helical MIC. It is suggested that the helical structure of the MamC-MIC is important for its function during magnetite formation.

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