... et al Staphylococcal nuclease refolding investigated Two point-mutated proteins, with a single base substitution of alanine for tryptophan (W14 0A) and alanine for lysine (K13 3A) , and two truncated ... both the wild-type protein and mutants E142O and K13 3A Thermal analysis of protein unfolding The DSC curves of the wild-type protein and the mutants K13 3A, E142O, W14 0A and W140O are shown in Fig ... Our CD and DSC data show that the W140 in SNase is the amino acid responsible for the stability of the whole protein However, in comparison with the wild-type protein, the mutant W14 0A retains significant...