Inhibition of glucose transport in human erythrocytes by cytochalasins: A model based on diffraction studies.

On the basis of details of the three-dimensional structures of beta-D-glucose and of cytochalasins, either previously published or reported here (cytochalasin A), we propose a model to explain the observed difference in activity of cytochalasins in the inhibition of glucose transport. In our model cytochalasin B binds to the glucose carrier through hydrogen bonds at N2 (donates), O7 (accepts), and O23 (accepts) analogous to O6, O3, and O1, respectively, on beta-D-glucose. The hydrophobic region from C13 to C19 is also essential in binding and appears to act as an anchor in a hydrophobic domain of the glucose carrier. The presence of hydrophilic groups in this essential hydrophobic region accounts, at least in part, for the inactivity of the other cytochalasins in the series.