FIGURE 5.

Li⁺ substitution and the Y268A mutation produce a similar pattern of perturbation of the interaction network across the TM domain. The two-dimensional representation of LeuT structure is as shown in Fig. 4. A black arrow is drawn between two subsegments if any of the residue pairs in these subsegments exhibits significant differences in the interaction frequencies (either larger or smaller) in the equilibrated stages of both Y268A.Na.ns and WT.Li.ns compared with the reference WT.Na.ns.