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Direct evidence of the molecular basis for biological silicon transport

Diatoms are an important group of eukaryotic algae with a curious evolutionary innovation: they sheath themselves in a cell wall made largely of silica. The cellular machinery responsible for silicification includes a family of membrane permeases that recognize and actively transport the soluble pre...

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Autores principales: Knight, Michael J., Senior, Laura, Nancolas, Bethany, Ratcliffe, Sarah, Curnow, Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4912633/
https://www.ncbi.nlm.nih.gov/pubmed/27305972
http://dx.doi.org/10.1038/ncomms11926
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author Knight, Michael J.
Senior, Laura
Nancolas, Bethany
Ratcliffe, Sarah
Curnow, Paul
author_facet Knight, Michael J.
Senior, Laura
Nancolas, Bethany
Ratcliffe, Sarah
Curnow, Paul
author_sort Knight, Michael J.
collection PubMed
description Diatoms are an important group of eukaryotic algae with a curious evolutionary innovation: they sheath themselves in a cell wall made largely of silica. The cellular machinery responsible for silicification includes a family of membrane permeases that recognize and actively transport the soluble precursor of biosilica, silicic acid. However, the molecular basis of silicic acid transport remains obscure. Here, we identify experimentally tractable diatom silicic acid transporter (SIT) homologues and study their structure and function in vitro, enabled by the development of a new fluorescence method for studying substrate transport kinetics. We show that recombinant SITs are Na(+)/silicic acid symporters with a 1:1 protein: substrate stoichiometry and K(M) for silicic acid of 20 μM. Protein mutagenesis supports the long-standing hypothesis that four conserved GXQ amino acid motifs are important in SIT function. This marks a step towards a detailed understanding of silicon transport with implications for biogeochemistry and bioinspired materials.
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spelling pubmed-49126332016-06-29 Direct evidence of the molecular basis for biological silicon transport Knight, Michael J. Senior, Laura Nancolas, Bethany Ratcliffe, Sarah Curnow, Paul Nat Commun Article Diatoms are an important group of eukaryotic algae with a curious evolutionary innovation: they sheath themselves in a cell wall made largely of silica. The cellular machinery responsible for silicification includes a family of membrane permeases that recognize and actively transport the soluble precursor of biosilica, silicic acid. However, the molecular basis of silicic acid transport remains obscure. Here, we identify experimentally tractable diatom silicic acid transporter (SIT) homologues and study their structure and function in vitro, enabled by the development of a new fluorescence method for studying substrate transport kinetics. We show that recombinant SITs are Na(+)/silicic acid symporters with a 1:1 protein: substrate stoichiometry and K(M) for silicic acid of 20 μM. Protein mutagenesis supports the long-standing hypothesis that four conserved GXQ amino acid motifs are important in SIT function. This marks a step towards a detailed understanding of silicon transport with implications for biogeochemistry and bioinspired materials. Nature Publishing Group 2016-06-16 /pmc/articles/PMC4912633/ /pubmed/27305972 http://dx.doi.org/10.1038/ncomms11926 Text en Copyright © 2016, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Knight, Michael J.
Senior, Laura
Nancolas, Bethany
Ratcliffe, Sarah
Curnow, Paul
Direct evidence of the molecular basis for biological silicon transport
title Direct evidence of the molecular basis for biological silicon transport
title_full Direct evidence of the molecular basis for biological silicon transport
title_fullStr Direct evidence of the molecular basis for biological silicon transport
title_full_unstemmed Direct evidence of the molecular basis for biological silicon transport
title_short Direct evidence of the molecular basis for biological silicon transport
title_sort direct evidence of the molecular basis for biological silicon transport
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4912633/
https://www.ncbi.nlm.nih.gov/pubmed/27305972
http://dx.doi.org/10.1038/ncomms11926
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