The cation diffusion facilitator protein MamM's cytoplasmic domain exhibits metal-type dependent binding modes and discriminates against Mn2+

Barber-Zucker, Shiran, Hall, Jenny, Froes, Afonso, Kolusheva, Sofiya, MacMillan, Fraser and Zarivach, Raz (2020) The cation diffusion facilitator protein MamM's cytoplasmic domain exhibits metal-type dependent binding modes and discriminates against Mn2+. The Journal of Biological Chemistry. ISSN 0021-9258

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Abstract

Cation diffusion facilitator (CDF) proteins are a conserved family of divalent transition metal cation transporters. CDF proteins are usually composed of two domains: the transmembrane domain (TMD), in which the metal cations are transported through, and a regulatory cytoplasmic C-terminal domain (CTD). Each CDF protein transports either one specific metal, or multiple metals, from the cytoplasm, and it is not known if the CTD takes an active regulatory role in metal recognition and discrimination during cation transport. Here, the model CDF protein MamM, an iron transporter from magnetotactic bacteria, was used to probe the role of the CTD in metal recognition and selectivity. Using a combination of biophysical and structural approaches, the binding of different metals to MamM CTD was characterized. Results reveal that different metals bind distinctively to MamM CTD in terms of their binding sites, thermodynamics and binding-dependent conformations, both in crystal form and in solution, which suggests a varying level of functional discrimination between CDF domains. Furthermore, these results provide the first direct evidence that CDF CTDs play a role in metal selectivity. We demonstrate that MamM's CTD can discriminate against Mn2+, supporting its postulated role in preventing magnetite formation poisoning in magnetotactic bacteria via Mn2+ incorporation.

Item Type: Article
Additional Information: Published under license by The American Society for Biochemistry and Molecular Biology, Inc.
Uncontrolled Keywords: deer,cation diffusion facilitator (cdf),mamm,epr spectroscopy,esr spectroscopy
Faculty \ School: Faculty of Science > School of Chemistry
Depositing User: LivePure Connector
Date Deposited: 13 Oct 2020 00:05
Last Modified: 19 Oct 2020 23:57
URI: https://ueaeprints.uea.ac.uk/id/eprint/77226
DOI: 10.1074/jbc.RA120.014145

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