Role of bound water and precipitants in the self-organization of biocrystals

It is shown that the unit cell parameters of biocrystals can be expressed as the sum of the pseudoperiods of a 30/11 helix composed of water molecules, which is the main element in the structure of the hydration shells of biocrystals. It is suggested that bound water molecules in the structure of a biocrystal form a lattice with edges that are essentially 30/11 helices spaced at a distance of the length of the corresponding pseudoperiod. An account is given of the role of precipitant in stabilizing this lattice. The conclusions are used to explain the polymorphism of biocrystals and the possible existence of large cavities and wide through channels in the structures of biocrystals in the case of polyethylene glycol and similar molecules of the corresponding length being used as a precipitant.