computer modeling in molecular biology.pdf

6 Theory of Transuort in Zon Channels 159Reactant to ProductReactant to Reactant2000 -10001500 1Eg 1000500 1 9 500c0 ;(D 0 :ae-500 1 9 -500- tt0-1000 e -1000-1500-2000-1.2 -0.8 -0.4 0 0.4 0.8 1.2t inps-Q-1500;-;--2000-1.2 -0.8 -0.4 0 0.4 0.8 1.2t inps20001500E1000P3 500eI!00-500L3g -1000Reactant to Product------IEf- C2000150010003 500I 0e9 -500gsL-1000Reactant to Reactant7-1500-1500-2000-1.2 -0.8 -0.4 0 0.4 0.8 1.2t inps-2000-1.2 -0.8 -0.4 0 0.4 0.8 1.2t inpsFigure 6-7. Typical example of the instantaneous forces acting on Na' ion during the reactivetrajectory, reactant to product, and the non-reactive trajectory, reactant to reactant, shownin Figure 6-6. The forces exerted by the channel and the two nearest water molecules areshown. The carbonyl forces are not dominant during the crossing event. The dominant forcescausing the recrossing arise primarily from the nearest carbonyl oxygens.reactive trajectory. During the successful crossing the water forces oscillate rapidlyand are predominant whereas the channel forces have moderate amplitude. Duringthe failed crossing the channel forces are much larger while the water forces havesimilar amplitudes than during the reactive trajectory, The nearest water molecules