185.

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Page 38

		1.3.6— The Physical Significance of the Scaling of Ion Channel Kinetics

		The scaling relationship in the timing of the switching between the open and closed states could be interpreted in two different ways:

		1. It could reflect the energy structure of the ion channel protein. The channel protein could exist in a large number of similar, but not identical, shapes. In this interpretation, the scaling relationship can be used to determine the heights of the energy barriers that separate the closed shapes from their corresponding open shapes.

		2. It could reflect the dynamics of how the shape of the ion channel protein changes in time. In this interpretation, the scaling relationship can be used to determine how the energy barrier between the closed state and the open state varies in time.

		The fractal approach focused attention on the dynamics, that is, the motions of the structures within ion channel proteins, on how past motions affect future behavior, and on the importance of the large number of slightly different shapes of the channel protein.

		The results of 20 years of experiments on other proteins also suggested that internal motions and the large numbers of possible protein shapes play an important role in how all proteins work.

		In contrast, most scientists who studied only ion channels had analyzed their data as if ion channel proteins had only a few states with fixed structures. Our work made some of these scientists very unhappy. Scientists, like anyone else, sometimes react with hostility to new ideas that challenge their beliefs and their previous work.

 

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