Protein‐engineering of chitosanase from Bacillus sp. MN to alter its substrate specificity. Issue 4 (19th January 2018)

• Record Type: Journal Article
• Authors: Regel, Eva K.; Weikert, Tobias; Niehues, Anna; Moerschbacher, Bruno M.; Singh, Ratna
• Is Part Of: Biotechnology and bioengineering. Volume 115:Issue 4(2018)
• Page Start: 863
• Page End: 873
• Publication Date: 2018-01-19
• Subjects: chitin -- chitooligosaccharides -- chitosan -- chitosanase -- glycoside hydrolase -- substrate specificity; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.26533
• Languages: English
• ISSNs: 0006-3592

Abstract

Abstract: Partially acetylated chitosan oligosaccharides (paCOS) have various potential applications in agriculture, biomedicine, and pharmaceutics due to their suitable bioactivities. One method to produce paCOS is partial chemical hydrolysis of chitosan polymers, but that leads to poorly defined mixtures of oligosaccharides. However, the effective production of defined paCOS is crucial for fundamental research and for developing applications. A more promising approach is enzymatic depolymerization of chitosan using chitinases or chitosanases, as the substrate specificity of the enzyme determines the composition of the oligomeric products. Protein‐engineering of these enzymes to alter their substrate specificity can overcome the limitations associated with naturally occurring enzymes and expand the spectrum of specific paCOS that can be produced. Here, engineering the substrate specificity of Bacillus sp. MN chitosanase is described for the first time. Two muteins with active site substitutions can accept N ‐acetyl‐D‐glucosamine units at their subsite (−2), which is impossible for the wildtype enzyme. Abstract : Protein‐engineering of Bacillus sp. MN chitosanase alters its substrate specificity on partially acetylated chitosan polymers. In contrast to the wild‐type enzyme, two muteins with active site substitutions accept N‐ acetyl‐D‐glucosamine units at their subsite (−2) when hydrolyzing chitosans. As the substrate specificity of the enzyme determines the composition of the oligomeric products, this approach overcomes limitations associated with naturally occurring enzymes and expands the spectrum of defined producible chitooligosaccharides.