Protein folding factors affecting

The above results and analysis on the low A in mononuclear and dinuclear cupredoxins have also been supported by numerous structural analyses of both oxidized and reduced cupredoxins. Both X-ray crystallography and XAS " of the metal-binding sites in the cupredoxins clearly show minimal difference between the oxidized and reduced proteins. Finally, in addition to the unique geometry and valence delocalization discussed above, which affect inner-sphere reorganization energy, other factors that may influence outer-sphere reorganization energy may also play an important role in cupredoxins. The factors include exclusion of water or solvent from the copper center in the folded proteins. This factor rules out electron transfer as a putative function for the red copper protein nitrosocyanin because its copper center is solvent accessible. 

Protein folding requires that the large conformational entropy opposing the folded state be outweighed by the sum of the enthalpic and other entropic factors that affect the stability of the folded state. The most important interactions determining the protein structure in water are briefly reviewed in the following sections. 

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