Inter-phylum structural conservation of the magnetosome-associated TPR-containing protein, MamA.
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.
Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel.
Natalie
N
Zeytuni
Dror
D
Baran
Geula
G
Davidov
Raz
R
Zarivach
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D006090:Gram-Negative Bacteria / Q000737:chemistry* / Q000145:classification / Q000235:genetics; D060526:Magnetic Fields; D055944:Magnetosomes / Q000737:chemistry*; D042201:Magnetospirillum / Q000737:chemistry / Q000235:genetics; D053768:Metal Nanoparticles / Q000737:chemistry; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D010802:Phylogeny; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
D001426:Bacterial Proteins; D011994:Recombinant Proteins