Abstract
Here the three-dimensional (3-D) structure of TRET1, a novel trehalose transporter from an anhydrobiotic insect, Polypedilum vanderplanki, was predicted by homology modeling in which the 3-D structure (1SUK) of GLUT1, glucose transporter from human was selected as a template. It was found that TRET1 has 12 transmembrane (TM) helices with an inward-facing conformation. Next, to explore the dynamics of the protein, we performed molecular dynamics (MD) simulation for the protein embedded in a hydrated phospholipid bilayer. The result of principal component analysis indicated that the protein has a hinge-bending motion, that is, the helices on the intracellular side come close or draw apart together. This dynamics may be essential for substrate uptake. Furthermore, we performed docking simulation combined with binding energy calculation to investigate the substrate selectivity of TRET1. As a result, it was found that trehalose more strongly binds to TRET1 than its isomer, isotrehalose, consistent with available experimental data.
