Evidence for difference in the roles of two cysteine residues involved in disulfide bond formation in the folding of human lysozyme.

摘要: Human lysozyme is made up of 130 amino acid residues and has four disulfide bonds at Cys6-Cys128, Cys30-Cys116, Cys65-Cys81, Cys77-Cys95. Our previous results using the Saccharomyces cerevisiae secretion system indicate that individual human have different functions in correct vivo folding enzymatic activity protein (Taniyama, Y., Yamamoto, Nakao, M., Kikuchi, Ikehara, M. (1988) Biochem. Biophys. Res. Commun. 152, 962-967). In this paper, we report experiments were focused on roles Cys65 Cys81 yeast. A mutant (C81A), which was replaced with Ala, had almost same conformation as those native enzyme. On other hand, another (C65A), not found to fold correctly. These a requisite for both activity, whereas indispensable. The C81A seen contain new, non-native bond Cys65-Cys77. possible occurrence interchange during our mapping cannot be ruled out by experimental techniques presently available, but characterization proteins computer analysis suggest intramolecular exchange present pathway vivo.