A novel family 19 chitinase from the marine-derived Pseudoalteromonas tunicata CCUG 44952T: Heterologous expression, characterization and antifungal activity

The Ptchi19 gene of the marine Pseudoatteromonas tunicata CCUG 44952T was cloned and expressed in Escherichia coli. The recombinant chitinase PtChi19p of 483 amino acids has a molecular weight of 53.5 kDa and a multi-domain structure characteristic of family 19 chitinases. The relevant constituents of this multi-domain structure are the domain (D-132-A(155)) where the active site is located, and the domain (A(437)-W-479) that includes a C-terminal carbohydrate-binding module 5. The purified protein was active in the temperature range of 20-50 degrees C and at pH values of 6-9.5, maintaining a high stability under suboptimal conditions and in the presence of different metal ions. The recombinant enzyme hydrolyzed colloidal and crystalline chitin, as well as p-NP N-acetyl-beta-D-glucosaminide. As PtChi19p exhibited antifungal activity against phytopathogenic and human pathogenic fungi, it could be used as an alternative biofungicide. (C) 2014 Elsevier B.V. All rights reserved.