Authors: Masahiro Nakajima Tetsuro Yamashita Machiko Takahashi Yuki Nakano Takumi Takeda
Publish Date: 2011/08/18
Volume: 93, Issue: 5, Pages: 1989-1998
Abstract
Hydrolytic enzymes responsible for laminarin degradation were found to be secreted during growth of Ustilago esculenta on laminarin An enzyme involved in laminarin degradation was purified by assaying release of glucose from laminaribiose Ionexchange chromatography of the culture filtrate followed by sizeexclusion chromatography yielded a 110kDa protein associated with laminaribiose hydrolysis LC/MS/MS analysis of the 110kDa protein identified three peptide sequences that shared significant similarity with a putative glucoside hydrolase family GH 3 βglucosidase in Ustilago maydis Based on the DNA sequence of the U maydis GH3 βglucosidase a gene encoding a putative GH3 βglucosidase in U esculenta Uebgl3A was cloned by PCR Based on the deduced amino acid sequence the protein encoded by Uebgl3A has a molecular mass of 91 kDa and shares 90 identity with U maydis GH3 βglucosidase Recombinant UeBgl3A expressed in Aspergillus oryzae released glucose from β13 β14 and β16linked oligosaccharides and from 1314βglucan and laminarin polysaccharides indicating that UeBgl3A is a βglucosidase Kinetic analysis showed that UeBgl3A preferentially hydrolyzed laminaritriose and laminaritetraose These results suggest that UeBgl3A is a key enzyme that produces glucose from laminarioligosaccharides during growth of U esculenta on laminarin
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