Integrating molecular probes and molecular dynamics to reveal binding modes of GLUT5 activatory and inhibitory ligands.

Fructose transporter GLUT5 is characterized by unusual substrate specificity and is linked to a variety of metabolic disorders. A series of high-affinity GLUT5-specific sugar-based probes - ManCous - have been very recently described and efficiently used as reporters of GLUT5 activity in cells. Here we present several 1 microsecond molecular dynamics (MD) simulations of GLUT5 and its complexes with fructose and two different ManCou probes, in a solvated cell membrane environment. These simulations show key molecular interactions within GLUT5 that promote the passage of the substrate through vs. blockage of the transport mechanism. Identification of these specific interactions and their long-range effects on GLUT5 structure and dynamics provides an essential basis for the future development of GLUT5-specific inhibitors.