Free energy surface of a sugar transporter in the presence and absence of substrate

Abstract

Mammalian sugar transporters typically participate in facilitated diffusion, carrying substrate across the lipid bilayer down its concentration gradient in a process known as the alternating access mechanism. The affinity for sugar of these transporters is low so as to quickly facilitate this exchange, yet they retain remarkably high substrate specificity. Given the sparse structural information about mammalian sugar transporters, there is little atomistic detail about their transport mechanism.