152 MACROMOLECULAR COMPLEXES 



siderable swelling. It is assumed that water is coordinated on the 

 protein layer located at the aqueous surface of each bimolecular 

 leaflet, the thickness of the water layer being largely determined by 

 the electrical charge density at these interfaces, and by the ionic 

 strength. As Schmitt (1959) has pointed out, these aqueous spaces 

 between the membranes play an important role as channels for the 

 products of metabolism, including ions, estabhshing contact be- 

 tween internal and external cellular spaces. The classic work of 

 Teorell (1958) has demonstrated that periodic transport of water 

 across the membranes and electroendosmotic phenomena are also 

 of fundamental importance in relation to the nerye mechanism. 



The effects of the electrically charged lipid groups on the struc- 

 ture of the hydration water in these aqueous interfaces may also 

 induce the formation of a "crystalline" aiTangement resembling the 

 "frozen" hydration sheaths postulated in protein molecules (Fer- 

 nandez-Moran, 1959b). According to Klotz (1958) and Klotz and 

 Luborsky ( 1959 ) , the induction of a crystalline lattice of hydration 

 water may be ascribed to the local and long-range cooperatiye elec- 

 tric field effects of the non-polar side-chains in proteins ( Frank and 

 Wen, 1957). The general problem of proton hydration and transfer 

 in aqueous solution is also of fundamental interest to the biologist. 

 According to the model proposed by Eigen and DeMaeyer (1959), 

 the proton exists as an H3O+ ion, connected to at least three addi- 

 tional HjO molecules by means of hydrogen bonds to form a H<)04 + 

 complex (Beckey, 1959) (primary hydration shell), with a proton 

 of excessiye mobility. The proton in ice behayes more like an elec- 

 tron than like an ion, having a mobility which is only 10 to 50 times 

 smaller than the mobility of an excited electron in iHuminated alkali 

 halide crystals. Eigen and DeMaeyer (1959) have pointed out that 

 these remarkable kinetic properties of protons may prove to be of 

 important biological significance. If we assume the existence of ice- 

 like hydration shells permeating the entire lipoprotein matrix, then 

 this high proton mobility would become an important factor to 

 reckon with in addition to the postulated electron mobility. 



Experimental Approaches for Correlation of Structure and 

 Function. It is against this background of a far more d}'namic pic- 

 ture involving migration of electrons, production of free radicals, 

 and the unique kinetic properties of protons that we must view the 

 experimental possibilities for establishing a closer correlation be- 

 tween ultrastructure and function in the ordered lamellar systems. 



