Direct evidence of the molecular basis for biological silicon transport

Michael Knight, Laura Senior, Bethany Nancolas, Sarah Ratcliffe, Paul Curnow

Research output: Contribution to journalArticle (Academic Journal)peer-review

18 Citations (Scopus)
255 Downloads (Pure)


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 KM 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.
Original languageEnglish
Article number11926
Number of pages11
JournalNature Communications
Early online date16 Jun 2016
Publication statusPublished - 16 Jun 2016

Structured keywords

  • Bristol BioDesign Institute
  • BrisSynBio


  • Biomineralization
  • Membrane Transport Proteins
  • Biogeochemistry

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