Degradation and Synthesis of β-Glucans by a Magnaporthe oryzae Endotransglucosylase, a Member of the Glycoside Hydrolase 7 Family

摘要: A Magnaporthe oryzae enzyme, which was encoded by the Mocel7B gene, predicted to act on 1,3–1,4-β-glucan degradation and transglycosylation reaction of cellotriose after partial purification from a culture filtrate M. cells, followed liquid chromatography-tandem mass spectrometry. recombinant MoCel7B prepared overexpression in exhibited endo-typical depolymerization polysaccharides containing β-1,4-linkages, best substrate. When cellooligosaccharides were used as substrate, enzyme generated products with both shorter longer chain lengths than In addition, incorporation glucose various oligosaccharides including sulforhodamine-conjugated cellobiose, laminarioligosaccharides, gentiobiose, xylobiose, mannobiose, xyloglucan nonasaccharide into β-1,4-linked glucans observed incubation enzyme. These results indicate that acts an endotransglucosylase (ETG) cleaves glycosidic bond β-1,4-glucan donor substrate transfers cleaved glucan another molecule functioning acceptor Furthermore, ETG treatment caused greater extension heat-treated wheat coleoptiles. The result suggests functions induce wall loosening cleaving tethers plant cell walls. On other hand, use cellohexaose for resulted production cellulose II maximum length (degree polymerization) 26 units. Thus, depolymerize polymerize β-glucans, depending size