Superoxide Dismutase as a Model Ion Channel
Detailed information is now available on the biochemistry and physiology of ion channels; however, with certain exceptions such as gramicidin (Wallace, 1984), far less is known about their structures. Moreover, atomic structures of ion channels may continue to be unobtainable for several years. Consequently, it seems worthwhile to consider how existing data on nonmembrane proteins might be used to suggest structural aspects of ion channels and hence aid in the design of relevant biochemical and physiological experiments. Two aspects of known protein structures are particularly pertinent to understanding the structural possibilities for membrane protein ion channels: the existence and nature of deep invaginations in the external molecular surfaces of proteins, and the role of electrostatic forces in the precollision guidance of ions. In this chapter, we use the high-resolution structure of the protein Cu, Zn Superoxide dismutase (SOD) as a model to illustrate these features, but the conclusions are representative of other known protein structures. In our analysis we make use of computer graphics techniques, which have been exceptionally successful for the display and evaluation of complex three-dimensional information.
KeywordsSuperoxide Dismutase Molecular Surface Metal Binding Site Deep Pocket Phenyl Glyoxal
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