Protein , conformational states dynamic properties

The perplexing difficulties that arise in the crystallization of macromolecules, in comparison with conventional small molecules, stem from the greater complexity, lability, and dynamic properties of proteins and nucleic acids. The description offered above of labile and metastable regions of supersaturation are still applicable to macromolecules, but it must now be borne in mind that as conditions are adjusted to transport the solution away from equilibrium by alteration of its physical and chemical properties, the very nature of the solute molecules is changing as well. As temperature, pH, pressure, or solvation are changed, so may be the conformation, charge state, or size of the solute macromolecules. 

It is now well established that the catalytic properties of a wide variety of enzymes remain intact in organic solvents (11-13). These findings imply that proteins may also retain their native struetures when lyophilized and dispersed in organic solvents. Evidence has been obtained that crystallized proteins have essentially the same structure in water and organic solvent (14,15). In the lyophilized state, proteins are also in a nonaqueous environment and it is expected their physico-chemical properties will differ from that in solution, as the dynamic conformational equilibria that exits in solution will be absent. Some physico-chemical studies indicate that the structure of the lyophilized state is very similar to that in solution (16-18), while others indicate that there is some limited but reversible conformational change (19-24). There are likely to be... 

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