Purification and some properties of endo-β-(1-3)-glucanase from the marine bivalve Chlamys abbidus

Two GH16 Endo-1,3-β-D-Glucanases from Formosa agariphila and F. algae Bacteria Have Complete Different Modes of Laminarin Digestion

There is a comparative analysis of primary structures and catalytic properties of two recombinant endo-1,3-β-D-glucanases from marine bacteria Formosa agariphila KMM 3901 and previously reported F. algae KMM 3553. Both enzymes had the same molecular mass 61 kDa, temperature optimum 45 °C, and comparable ranges of thermal stability and Km. While the set of products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. algae was stable of the reaction with pH 4-9, the pH stability of the products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. agariphila varied at pH 5-6 for DP 2, at pH 4 and 7-8 for DP 5, and at pH 9 for DP 3. There were differences in modes of action of these enzymes on laminarin and 4-methylumbelliferyl-β-D-glucoside (Umb), indicating the presence of transglycosylating activity of endo-1,3-β-D-glucanase from F. algae and its absence in endo-1,3-β-D-glucanase from F. agariphila. While endo-1,3-β-D-glucanase from F. algae produced transglycosylated laminarioligosaccharides with a degree of polymerization 2-10 (predominately 3-4), endo-1,3-β-D-glucanase from F. agariphila did not catalyze transglycosylation in our lab parameters.

Purification, cDNA cloning and homology modeling of endo-1,3-β-d-glucanase from scallop Mizuhopecten yessoensis

The retaining endo-1,3-beta-D-glucanase (LV) with molecular mass of 36 kDa was purified to homogeneity from the crystalline styles of scallop Mizuhopecten yessoensis. The purified enzyme catalyzed hydrolysis of laminaran as endo-enzyme forming glucose, laminaribiose and higher oligosaccharides as products (Km approximately 600 microg/mL). The 1,3-beta-D-glucanase effectively catalyzed transglycosylation reaction that is typical of endo-enzymes too. Optima of pH and temperature were at 4.5 and 45 degrees C, respectively. cDNA encoding the endo-1,3-beta-D-glucanase was cloned by PCR-based methods. It contained an open reading frame that encoded 339-amino acids protein. The predicted endo-1,3-beta-D-glucanase amino acid sequence included a characteristic domain of the glycosyl hydrolases family 16 and revealed closest homology with 1,3-beta-D-glucanases from bivalve Pseudocardium sachalinensis, sea urchin Strongylocentrotus purpuratus and invertebrates lipopolysaccharide and beta-1,3-glucan-binding proteins. The fold of the LV was more closely related to kappa-carrageenase, agarase and 1,3;1,4-beta-D-glucanase from glycosyl hydrolases family 16. Homology model of the endo-1,3-beta-D-glucanase from M. yessoensis was obtained with MOE on the base of the crystal structure of kappa-carrageenase from P. carrageonovora as template. Putative three-dimensional structures of the LV complexes with substrate laminarihexaose or glucanase inhibitor halistanol sulfate showed that the binding sites of the halistanol sulfate and laminarihexaose are located in the enzyme catalytic site and overlapped.