Peptide Transporter Function & Structure
Human promiscuous peptide transporter 1 (PepT1) plays a crucual role in nutrition, transporting di- and tri-peptides from digested protein into intestinal cells.[1] It is also crucial in uptake of orally delivered drugs.[1] It is a member of the proton-coupled oligopeptide transporter (POT) family. These secondary active transporters are powered by the inward-directed electrochemical proton gradient, enabling intracellular accumulation of peptides/drugs above extracellular concentrations.[1].
with an extracellular domain (beta sheets), and a transmembrane transporter domain (alpha helices) with a cytoplasmic amphipathic 2-helix linker (green protrusion). The latter looks like the toe of a boot formed by the linker (toe) with the transmembrane domain. The function of the extracellular and cytoplasmic linker domains are not well understood, although the extracellular domain appears to be important in transport[2].
The transmembrane domain has a (enabling it to sit within the lipid bilayer membrane) which is . The cytoplamic linker "toe" has a net positive charge, enabling it to bind to the inner leaflet of the lipid bilayer, which typically has a negative charge.
Rocker-Switch Transport Mechanism
PepT1
Green Links
outward facing morph spacefilled showing dipeptide visible/hidden
