Podar, D., Scherer, J., Noordally, Z., Herzyk, P. , Nies, D. and Sanders, D. (2012) Metal selectivity determinants in a family of transition metal transporters. Journal of Biological Chemistry, 287(5), pp. 3185-3196. (doi: 10.1074/jbc.M111.305649)
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Abstract
Metal Tolerance Proteins (MTPs) are plant members of the Cation Diffusion Facilitator (CDF) transporter family involved in cellular metal homeostasis. Members of the CDF family are ubiquitously found in all living entities and show principal selectivity for Zn2+, Mn2+ and Fe2+. Little is known with respect to metal selectivity determinants of CDFs. We identified a novel cereal member of CDFs in barley termed HvMTP1 that localizes to the vacuolar membrane. Unlike its close relative AtMTP1 that is highly selective for Zn2+, HvMTP1 exhibits selectivity for both Zn2+ and Co2+ as assessed by its ability to suppress yeast mutant phenotypes for both metals. Expression of HvMTP1/AtMTP1 chimeras in yeast revealed a five-residue sequence within the AtMTP1 N-segment of the His-rich intracytoplasmic loop that confines specificity to Zn2+. Furthermore, mutants of AtMTP1 generated through random mutagenesis revealed residues embedded within Transmembrane Domain 3 (TMD3) that additionally specify the high degree of Zn2+ selectivity. We propose that the His-rich loop, which might play a role as a zinc chaperone, determines the identity of the metal ions that are transported. The residues within TMD3 can also influence metal selectivity, possibly through conformational changes induced at the cation transport site located within the membrane or at the cytoplasmic C-terminal domain.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Herzyk, Dr Pawel |
| Authors: | Podar, D., Scherer, J., Noordally, Z., Herzyk, P., Nies, D., and Sanders, D. |
| College/School: | College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing |
| Journal Name: | Journal of Biological Chemistry |
| Journal Abbr.: | J Biol Chem. |
| Publisher: | American Society for Biochemistry and Molecular Biology, Inc. |
| ISSN: | 0021-9258 |
| ISSN (Online): | 1083-351X |
| Published Online: | 02 December 2011 |
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