title: Hyperproduction of β-Glucanase Exg1 Promotes the Bioconversion of Mogrosides in Saccharomyces cerevisiae Mutants Defective in Mannoprotein Deposition.
abstract: Bacteria and fungi can secrete extracellular enzymes to convert macromolecules into smaller units. Hyperproduction of extracellular enzymes is often associated with alterations in cell wall structure in fungi. Recently, we identified that Saccharomyces cerevisiae kre6Δ mutants can efficiently convert mogroside V into mogroside III E, which has antidiabetic properties. However, the underlying efficient bioconversion mechanism is unclear. In the present study, the mogroside (MG) bioconversion properties of several cell wall structure defective mutants were analyzed. We also compared the cell walls of these mutants by transmission electron microscopy, a zymolyase sensitivity test, and a mannoprotein release assay. We found zymolyase-sensitive mutants (including kre1Δ, las21Δ, gas1Δ, and kre6Δ), with defects in mannoprotein deposition, exhibit efficient MG conversion and excessive leakage of Exg1; such defects were not observed in wild-type cells, or mutants with abnormal levels of glucans in the cell wall. Thus, yeast mutants defective in mannoprotein deposition may be employed to convert glycosylated bioactive compounds.
authors.affiliation: Institute of Food Science and Technology, National Taiwan University , No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Reuben
authors.initials: R
authors.lastname: Wang
authors.affiliation: College of Bioresources and Agriculture, Joint Center for Instruments and Researches , No. 81, Changxing Street, Da-an District, Taipei 10617, Taiwan.
authors.forename: Pei-Yin
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Food Industry Research Development Institute, Bioresource Collection and Research Center , No. 331, Shih-Pin Road, Hsinchu 30062, Taiwan.
authors.forename: Shyue-Tsong
authors.initials: ST
authors.lastname: Huang
authors.affiliation: Institute of Food Science and Technology, National Taiwan University , No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Chiu
authors.affiliation: Institute of Food Science and Technology, National Taiwan University , No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.|College of Bioresources and Agriculture, Joint Center for Instruments and Researches , No. 81, Changxing Street, Da-an District, Taipei 10617, Taiwan.
authors.forename: Ting-Jang
authors.initials: TJ
authors.lastname: Lu
authors.affiliation: Institute of Food Science and Technology, National Taiwan University , No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Lo
mesh_terms: D001711:Biotransformation; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014315:Triterpenes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008562:Membrane Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D014315:Triterpenes; C025363:mannoproteins; C468487:EXG1 protein, S cerevisiae; D043326:Glucan 1,3-beta-Glucosidase
keywords: EXG1; KRE6; Saccharomyces cerevisiae; bioconversion; mannoprotein; mogrosides