Divalent metal transport in the green microalga <Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis> is mediated by a protein similar to prokaryotic Nramp homologues |
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Authors: | Alexandra?Rosakis Email author" target="_blank">Wolfgang?K?sterEmail author |
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Institution: | (1) Environmental Microbiology and Molecular Ecotoxicology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), überlandstrasse 133, CH-8600 Duebendorf, Switzerland;(2) VIDO – Vaccine & Infectious Diseases Organization, University of Saskatchewan, VIDO Building, 120 Veterinary Rd., Saskatoon, S7N 5E3, Saskatchewan, Canada |
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Abstract: | Information about the molecular mechanisms of metal transport in algae is scarce, despite the significant status these organisms
have in aquatic ecosystems. In the present study, we describe the cloning and functional characterization of a divalent metal
transporter (named DMT1) in the green microalga Chlamydomonas reinhardtii Dangeard. The longest open reading frame of the cloned DMT1 cDNA encodes a protein of 513 amino acids with 11 putative transmembrane
domains. The protein belongs to the Nramp family of divalent metal transporters and shows surprisingly higher similarity to
some prokaryotic than to eukaryotic polypeptides. Especially the N-terminus, which is longer than of every other homologue
considered in this study, displays – uniquely among selected eukaryotic Nramps – exclusively prokaryotic characteristics.
Functional complementation experiments in yeast strains with impaired metal transport systems, revealed that C. reinhardtii DMT1 has a broad specificity, acting in the transport of several divalent metals (manganese, iron, cadmium, copper), but
excluding zinc.
Published online December 2004 |
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Keywords: | Chlamydomonas reinhardtii divalent metal transport DMT1 green algae Nramp |
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