PDBsum entry 3as8

Protein binding

PDB id: 3as8

Contents

Protein chain

181 a.a.

Ligands

SO4 ×3

Waters ×238

PDB id:

3as8

Name:

Protein binding

Title:

Mama msr-1 p41212

Structure:

Magnetosome protein mama. Chain: a. Fragment: unp residues 41-217. Synonym: magnetosome protein mama, tpr-like. Engineered: yes

Source:

Magnetospirillum gryphiswaldense. Organism_taxid: 431944. Strain: msr-1. Gene: mama, mgi495, mgr_4099. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.00Å R-factor: 0.181 R-free: 0.225

Authors:

N.Zeytuni,G.Davidov,R.Zarivach

Key ref:

N.Zeytuni et al. (2011). Self-recognition mechanism of MamA, a magnetosome-associated TPR-containing protein, promotes complex assembly. Proc Natl Acad Sci U S A, 108, E480. PubMed id: 21784982

Date:

10-Dec-10 Release date: 20-Jul-11

Protein chain

Q93DY9  (MAMA_MAGGM) -  Magnetosome protein MamA from Magnetospirillum gryphiswaldense (strain DSM 6361 / JCM 21280 / NBRC 15271 / MSR-1)

Seq: 217 a.a.

Struc: 181 a.a.

Proc Natl Acad Sci U S A 108:E480 (2011)

PubMed id: 21784982

Self-recognition mechanism of MamA, a magnetosome-associated TPR-containing protein, promotes complex assembly.

N.Zeytuni, E.Ozyamak, K.Ben-Harush, G.Davidov, M.Levin, Y.Gat, T.Moyal, A.Brik, A.Komeili, R.Zarivach.

ABSTRACT

The magnetosome, a biomineralizing organelle within magnetotactic bacteria, allows their navigation along geomagnetic fields. Magnetosomes are membrane-bound compartments containing magnetic nanoparticles and organized into a chain within the cell, the assembly and biomineralization of magnetosomes are controlled by magnetosome-associated proteins. Here, we describe the crystal structures of the magnetosome-associated protein, MamA, from Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1. MamA folds as a sequential tetra-trico-peptide repeat (TPR) protein with a unique hook-like shape. Analysis of the MamA structures indicates two distinct domains that can undergo conformational changes. Furthermore, structural analysis of seven crystal forms verified that the core of MamA is not affected by crystallization conditions and identified three protein-protein interaction sites, namely a concave site, a convex site, and a putative TPR repeat. Additionally, relying on transmission electron microscopy and size exclusion chromatography, we show that highly stable complexes form upon MamA homooligomerization. Disruption of the MamA putative TPR motif or N-terminal domain led to protein mislocalization in vivo and prevented MamA oligomerization in vitro. We, therefore, propose that MamA self-assembles through its putative TPR motif and its concave site to create a large homooligomeric scaffold which can interact with other magnetosome-associated proteins via the MamA convex site. We discuss the structural basis for TPR homooligomerization that allows the proper function of a prokaryotic organelle.