| Structural highlights
Function
MAMO_PARM1 Plays 2 roles; promotes magnetite nucleation/formation and activates the MamE protease (Probable). Despite its near conservation of a protease-like sequence, this is probably not a protease (Probable) (PubMed:26981620). Required in conjunction with MamP for proteolysis of at least MamE, itself and MamP (PubMed:26981620). May transport a solute that controls MamE's protease activity. May place individual iron atoms into the magnetite lattice (Probable).[1] [2] [3] [4]
Publication Abstract from PubMed
Many living organisms transform inorganic atoms into highly ordered crystalline materials. An elegant example of such biomineralization processes is the production of nano-scale magnetic crystals in magnetotactic bacteria. Previous studies implicated the involvement of two putative serine proteases, MamE and MamO, during the early stages of magnetite formation in Magnetospirillum magneticum AMB-1. Here, using genetic analysis and X-ray crystallography, we show that MamO has a degenerate active site, rendering it incapable of protease activity. Instead, MamO promotes magnetosome formation through two genetically distinct, noncatalytic activities: activation of MamE-dependent proteolysis of biomineralization factors and direct binding to transition metal ions. By solving the structure of the protease domain bound to a metal ion, we identify a surface-exposed di-histidine motif in MamO that contributes to metal binding and show that it is required to initiate biomineralization in vivo. Finally, we find that pseudoproteases are widespread in magnetotactic bacteria and that they have evolved independently in three separate taxa. Our results highlight the versatility of protein scaffolds in accommodating new biochemical activities and provide unprecedented insight into the earliest stages of biomineralization.
MamO Is a Repurposed Serine Protease that Promotes Magnetite Biomineralization through Direct Transition Metal Binding in Magnetotactic Bacteria.,Hershey DM, Ren X, Melnyk RA, Browne PJ, Ozyamak E, Jones SR, Chang MC, Hurley JH, Komeili A PLoS Biol. 2016 Mar 16;14(3):e1002402. doi: 10.1371/journal.pbio.1002402., eCollection 2016 Mar. PMID:26981620[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hershey DM, Ren X, Melnyk RA, Browne PJ, Ozyamak E, Jones SR, Chang MC, Hurley JH, Komeili A. MamO Is a Repurposed Serine Protease that Promotes Magnetite Biomineralization through Direct Transition Metal Binding in Magnetotactic Bacteria. PLoS Biol. 2016 Mar 16;14(3):e1002402. doi: 10.1371/journal.pbio.1002402., eCollection 2016 Mar. PMID:26981620 doi:http://dx.doi.org/10.1371/journal.pbio.1002402
- ↑ Murat D, Quinlan A, Vali H, Komeili A. Comprehensive genetic dissection of the magnetosome gene island reveals the step-wise assembly of a prokaryotic organelle. Proc Natl Acad Sci U S A. 2010 Mar 23;107(12):5593-8. PMID:20212111 doi:10.1073/pnas.0914439107
- ↑ Quinlan A, Murat D, Vali H, Komeili A. The HtrA/DegP family protease MamE is a bifunctional protein with roles in magnetosome protein localization and magnetite biomineralization. Mol Microbiol. 2011 May;80(4):1075-87. PMID:21414040 doi:10.1111/j.1365-2958.2011.07631.x
- ↑ Hershey DM, Ren X, Melnyk RA, Browne PJ, Ozyamak E, Jones SR, Chang MC, Hurley JH, Komeili A. MamO Is a Repurposed Serine Protease that Promotes Magnetite Biomineralization through Direct Transition Metal Binding in Magnetotactic Bacteria. PLoS Biol. 2016 Mar 16;14(3):e1002402. doi: 10.1371/journal.pbio.1002402., eCollection 2016 Mar. PMID:26981620 doi:http://dx.doi.org/10.1371/journal.pbio.1002402
- ↑ Hershey DM, Ren X, Melnyk RA, Browne PJ, Ozyamak E, Jones SR, Chang MC, Hurley JH, Komeili A. MamO Is a Repurposed Serine Protease that Promotes Magnetite Biomineralization through Direct Transition Metal Binding in Magnetotactic Bacteria. PLoS Biol. 2016 Mar 16;14(3):e1002402. doi: 10.1371/journal.pbio.1002402., eCollection 2016 Mar. PMID:26981620 doi:http://dx.doi.org/10.1371/journal.pbio.1002402
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