Identification of the peptide region that folds native conformation in the early stage of the renaturation of reduced lysozyme.

We prepared three peptide fragments (fg.59-105, fg.63-105 and fg.64-105) by the BrCN cleavage of mutant lysozymes where Ile58, Trp62 and Trp63 were mutated to Met, respectively. From the analysis of formation of the disulfide bonds among Cys64, Cys76, Cys80 and Cys94 in the renaturation of each peptide fragment from the reduced form, Trp62 and Trp63 were required for the effective formation of two disulfide bonds. Especially, Trp62 was found to be involved in the correct formation of the disulfide bonds.