title: Divalent metal transport in the green microalga Chlamydomonas reinhardtii is mediated by a protein similar to prokaryotic Nramp homologues.
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.
authors.affiliation: Environmental Microbiology and Molecular Ecotoxicology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Uberlandstrasse 133, CH-8600 Duebendorf, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rosakis
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Köster
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002104:Cadmium / Q000494:pharmacology; D019256:Cadmium Chloride / Q000494:pharmacology; D002352:Carrier Proteins / Q000737:chemistry; D027682:Cation Transport Proteins / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology; D003001:Cloning, Molecular; D003300:Copper / Q000494:pharmacology; D019327:Copper Sulfate / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000737:chemistry; D005816:Genetic Complementation Test; D007501:Iron / Q000494:pharmacology; D033862:Iron-Binding Proteins / Q000378:metabolism; D008345:Manganese / Q000494:pharmacology; D008670:Metals / Q000378:metabolism*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D010455:Peptides / Q000737:chemistry; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012984:Software; D015032:Zinc / Q000737:chemistry; D017967:Zinc Compounds / Q000494:pharmacology; D000099173:Natural Resistance-associated Macrophage Protein 1; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D002104:Cadmium; D019256:Cadmium Chloride; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D002712:Chlorides; D003300:Copper; D019327:Copper Sulfate; D018076:DNA, Complementary; D004492:Edetic Acid; D007501:Iron; D033862:Iron-Binding Proteins; D008345:Manganese; D008670:Metals; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D015032:Zinc; D017967:Zinc Compounds; D000099173:Natural Resistance-associated Macrophage Protein 1; D000099236:Solute Carrier Family 11, Member 2; C105116:SMF1 protein, S cerevisiae; C016837:zinc chloride