Structure-function studies of the magnetite-biomineralizing magnetosome-associated protein MamC

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• 作者：Hila Nudelman^a ; Carmen Valverde-Tercedor^b ; ^c ; Sofiya Kolusheva^d ; Teresa Perez Gonzalez^b ; Marc Widdrat^d ; Noam Grimberg^a ; Hilla Levi^a ; Or Nelkenbaum^a ; Geula Davidov^a ; Damien Faivre^d ; Concepcion Jimenez-Lopez^b ; ^{cjl@ugr.es" class="auth_mail" title="E-mail the corresponding author} ; Raz Zarivach^a ; ^{zarivach@bgu.ac.il" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Biomineralization ; Magnetotactic bacteria ; MamC ; Protein structure ; Structure&ndash ; activity relationships
• 刊名：Journal of Structural Biology
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：194
• 期：3
• 页码：244-252
• 全文大小：2020 K

文摘

Magnetotactic bacteria are Gram-negative bacteria that navigate along geomagnetic fields using the magnetosome, an organelle that consists of a membrane-enveloped magnetic nanoparticle. Magnetite formation and its properties are controlled by a specific set of proteins. MamC is a small magnetosome-membrane protein that is known to be active in iron biomineralization but its mechanism has yet to be clarified. Here, we studied the relationship between the MamC magnetite-interaction loop (MIL) structure and its magnetite interaction using an inert biomineralization protein-MamC chimera. Our determined structure shows an alpha-helical fold for MamC-MIL with highly charged surfaces. Additionally, the MamC-MIL induces the formation of larger magnetite crystals compared to protein-free and inert biomineralization protein control experiments. We suggest that the connection between the MamC-MIL structure and the protein’s charged surfaces is crucial for magnetite binding and thus for the size control of the magnetite nanoparticles.