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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...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2016
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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. |
format | Online Article Text |
id | pubmed-4912633 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
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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