| Structural highlights
Function
MAMK_MAGSA Protein with ATPase activity which forms dynamic cytoplasmic filaments (probably with paralog MamK-like) that organize magnetosomes into long chains running parallel to the long axis of the cell (Probable) (PubMed:21883528, PubMed:28790202, PubMed:23204522, PubMed:24957623). Turnover of MamK filaments is probably promoted by MamK-like, which provides a monomer pool (PubMed:24957623). Forms twisted filaments in the presence of ATP or GTP (PubMed:20161777, PubMed:23204522, PubMed:27391173). Serves to close gaps between magnetosomes in the chain (PubMed:26884433). Interaction with MCP10 is involved in controlling the response to magnetic fields, possibly by controlling flagellar rotation (PubMed:20471399). Expression in E.coli yields a filament in the cell's longitudinal axis; the protein nucleates at several sites and one extremity of the filament is located at the cell pole (PubMed:17085581, PubMed:20161777).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Publication Abstract from PubMed
Magnetotactic bacteria possess cellular compartments called magnetosomes that sense magnetic fields. Alignment of magnetosomes in the bacterial cell is necessary for their function, and this is achieved through anchoring of magnetosomes to filaments composed of the protein MamK. MamK is an actin homologue that polymerizes upon ATP binding. Here, we report the structure of the MamK filament at approximately 6.5 A, obtained by cryo-Electron Microscopy. This structure confirms our previously reported double-stranded, non-staggered architecture, and reveals the molecular basis for filament formation. While MamK is closest in sequence to the bacterial actin MreB, the longitudinal contacts along each MamK strand most closely resemble those of eukaryotic actin. In contrast, the cross-strand interface, with a surprisingly limited set of contacts, is novel among actin homologues and gives rise to the non-staggered architecture. This article is protected by copyright. All rights reserved.
Structure of the Magnetosome-associated actin-like MamK filament at sub-nanometer resolution.,Bergeron JR, Hutto R, Ozyamak E, Hom N, Hansen J, Draper O, Byrne ME, Keyhani S, Komeili A, Kollman JM Protein Sci. 2016 Jul 8. doi: 10.1002/pro.2979. PMID:27391173[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Pradel N, Santini CL, Bernadac A, Fukumori Y, Wu LF. Biogenesis of actin-like bacterial cytoskeletal filaments destined for positioning prokaryotic magnetic organelles. Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17485-9. PMID:17085581 doi:10.1073/pnas.0603760103
- ↑ Rioux JB, Philippe N, Pereira S, Pignol D, Wu LF, Ginet N. A second actin-like MamK protein in Magnetospirillum magneticum AMB-1 encoded outside the genomic magnetosome island. PLoS One. 2010 Feb 10;5(2):e9151. PMID:20161777 doi:10.1371/journal.pone.0009151
- ↑ Philippe N, Wu LF. An MCP-like protein interacts with the MamK cytoskeleton and is involved in magnetotaxis in Magnetospirillum magneticum AMB-1. J Mol Biol. 2010 Jul 16;400(3):309-22. PMID:20471399 doi:10.1016/j.jmb.2010.05.011
- ↑ Draper O, Byrne ME, Li Z, Keyhani S, Barrozo JC, Jensen G, Komeili A. MamK, a bacterial actin, forms dynamic filaments in vivo that are regulated by the acidic proteins MamJ and LimJ. Mol Microbiol. 2011 Oct;82(2):342-54. PMID:21883528 doi:10.1111/j.1365-2958.2011.07815.x
- ↑ Ozyamak E, Kollman J, Agard DA, Komeili A. The bacterial actin MamK: in vitro assembly behavior and filament architecture. J Biol Chem. 2013 Feb 8;288(6):4265-77. PMID:23204522 doi:10.1074/jbc.M112.417030
- ↑ Abreu N, Mannoubi S, Ozyamak E, Pignol D, Ginet N, Komeili A. Interplay between two bacterial actin homologs, MamK and MamK-Like, is required for the alignment of magnetosome organelles in Magnetospirillum magneticum AMB-1. J Bacteriol. 2014 Sep;196(17):3111-21. PMID:24957623 doi:10.1128/JB.01674-14
- ↑ Cornejo E, Subramanian P, Li Z, Jensen GJ, Komeili A. Dynamic Remodeling of the Magnetosome Membrane Is Triggered by the Initiation of Biomineralization. mBio. 2016 Feb 16;7(1):e01898-15. PMID:26884433 doi:10.1128/mBio.01898-15
- ↑ Bergeron JR, Hutto R, Ozyamak E, Hom N, Hansen J, Draper O, Byrne ME, Keyhani S, Komeili A, Kollman JM. Structure of the Magnetosome-associated actin-like MamK filament at sub-nanometer resolution. Protein Sci. 2016 Jul 8. doi: 10.1002/pro.2979. PMID:27391173 doi:http://dx.doi.org/10.1002/pro.2979
- ↑ Taoka A, Kiyokawa A, Uesugi C, Kikuchi Y, Oestreicher Z, Morii K, Eguchi Y, Fukumori Y. Tethered Magnets Are the Key to Magnetotaxis: Direct Observations of Magnetospirillum magneticum AMB-1 Show that MamK Distributes Magnetosome Organelles Equally to Daughter Cells. mBio. 2017 Aug 8;8(4):e00679-17. PMID:28790202 doi:10.1128/mBio.00679-17
- ↑ Komeili A, Li Z, Newman DK, Jensen GJ. Magnetosomes are cell membrane invaginations organized by the actin-like protein MamK. Science. 2006 Jan 13;311(5758):242-5. PMID:16373532 doi:10.1126/science.1123231
- ↑ Bergeron JR, Hutto R, Ozyamak E, Hom N, Hansen J, Draper O, Byrne ME, Keyhani S, Komeili A, Kollman JM. Structure of the Magnetosome-associated actin-like MamK filament at sub-nanometer resolution. Protein Sci. 2016 Jul 8. doi: 10.1002/pro.2979. PMID:27391173 doi:http://dx.doi.org/10.1002/pro.2979
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