Proposed model of silicon transport through the 10-transmembrane diatom transporter. The outward-facing conformation binds extracelllar silicate through hydrogen bonding to 2 conserved Gln in the transmembrane helices 7 and 8. A conformational change to an inward-facing conformation allows silicate to bind to other conserved Gln in the loop between helices 2 and 3, releasing silicate into the cell to be bound by as yet unknown components. Reproduced with permission from [36].
