Influence of disulfide bonds on the induction of helical conformation in proteins

The effect(s) of TFE (2,2,2-trifluoroethanol) on three different conformati onal states (native, denatured, and carboxymethylated) of CTX III and RNase A has been examined. Contrary to the general belief, the results of the pr esent study reveal that TFE can induce helical conformation in a protein wh ich has no sequence propensity to form a helix. It is found that the helix induction in TFE is intricately related to the destabilization of the terti ary structural conformation in proteins. More importantly, the disulfide bo nds in proteins are found to have significant influence on the TFE-mediated helix induction. The results obtained in this study strongly suggest that information pertaining to the influence of disulfide bonds on helix inducti on need to be considered to improve the accuracy of secondary structure pre diction algorithms.