MamA AMB-1 P212121

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.179 

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

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

(2011) Proc Natl Acad Sci U S A 108: E480-E487

  • DOI: https://doi.org/10.1073/pnas.1103367108
  • Primary Citation of Related Structures:  
    3AS4, 3AS5, 3AS8, 3ASD, 3ASF, 3ASG, 3ASH

  • PubMed 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.

  • Organizational Affiliation

    Department of Life Sciences, Ben Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
186Magnetospirillum magneticum AMB-1Mutation(s): 0 
Gene Names: mam22mamAmms24amb0971
Find proteins for Q2W8Q0 (Magnetospirillum magneticum (strain AMB-1 / ATCC 700264))
Explore Q2W8Q0 
Go to UniProtKB:  Q2W8Q0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ2W8Q0
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on MG

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.179 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.75α = 90
b = 76.194β = 90
c = 105.057γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-07-20
    Type: Initial release
  • Version 1.1: 2013-06-26
    Changes: Database references