Effects of the N-terminus of keratinase from Bacillus licheniformis on activity and thermostability

Abstract:

[Objective] In order to functional analysis the N-terminus of keratinase from Bacillus licheniformis and its effect on the activity and thermostability of keratinase, the N-terminus of keratinase was reconstructed by molecular modification. [Methods] The N-terminus residues of keratinase were deleted individually and replaced by an N-terminus of thermitase from Thermoactinomyces vulgaris through sequence alignment. The recombinant keratinases of wild-type and mutants were production in Bacillus subtilis WB600 and then purified for characterization. [Results] Deletion of N-terminus of keratinase resulted in enzyme activity decreased prominently, when deficiency of five residues the activity of enzyme was completely abolished. Although replacement of N-terminus from thermitase decreased the activity of keratinase, the thermostability of mutant was enhanced compared with wild-type. The half-live of thermal inactivation (t1/2) was enhanced from 9 to 20 min at 60 °C. [Conclusion] The N-terminus of keratinase was important for enzyme activity, replacement of N-terminus between keratinase and thermitase could efficient enhanced thermostability of keratinase.

Key words:Keratinase, N-terminus, Thermostability