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Publication Abstract from PubMed

Magnetotactic bacteria enclose the magnetosome, a unique prokaryotic sub-cellular organelle that allows the biomineralization of magnetic nano-crystals. Membrane-coated magnetosomes are arranged into a linear chain that permits magnetotactic bacteria to navigate geomagnetic fields. Magnetosome assembly and biomineralization are controlled by conserved magnetosome-associated proteins, including MamA, a tetra-trico-peptide repeat (TPR)-containing protein that was shown to coat the magnetosome membrane. In this study, two MamA structures from Candidatus Magnetobacterium bavaricum (Mbav) were determined via X-ray crystallography. These structures confirm that Mbav MamA folds as a sequential TPR protein and shares a high degree of structural similarity with homologous MamA proteins from Magnetospirillum species. Furthermore, the two TPR-containing domains of MamA are separated by an interphylum-conserved region containing a flexible hinge that is involved in ligand binding and recognition. Finally, substantial differences were found in the local stabilization of the MamA N-terminal domain as a result of the loss of an evolutionary conserved salt bridge.

Inter-phylum structural conservation of the magnetosome-associated TPR-containing protein, MamA.,Zeytuni N, Baran D, Davidov G, Zarivach R J Struct Biol. 2012 Dec;180(3):479-87. doi: 10.1016/j.jsb.2012.08.001. Epub 2012 , Aug 15. PMID:22917855^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.