Enzymatic synthesis and characterization of beta-1,6-glucan

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K07504
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Wood science
• Research Institution: Utsunomiya University
• Principal Investigator: KONNO NAOTAKE 宇都宮大学, 農学部, 准教授 (60549880)
• Research Collaborator: NAKAMURA mai ; HONGO arisa
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: きのこ / βグルカン / 糖質関連酵素

Outline of Final Research Achievements

Beta-1,6-glucan, a cell wall component of fungi, is known as a bioactive (antitumor) polysaccharide. In this study, the cDNAs encoding Beta-1,6-glucan degrading enzymes (Beta-1,6-glucanases) were cloned from basidiomycetes, and two Beta-1,6-glucanases, Sc30 (from Schizophyllum commune) and Cc30 (from Coprinopsis cinerea), were heterologously expressed in Aspergillus oryzae. Sc30 (57 kDa) and Cc30 (50 kDa) catalyzed depolymerization of Beta-1,6-glucan endolytically, and were highly specific toward Beta-1,6-glucan polysaccharide. The enzymes were most active at pH 5.0. We prepared glycosynthase mutants using the Beta-1,6-glucanases, Sc30 and Cc30. Some prepared Beta-glucan oligosaccharides with various structures showed the immunostimulatory activity on murine macrophage-like cells. It was suggested that these functional oligomers were consisted of Beta-1,6-linkages, and their degree of polymerization were greater than five.

Free Research Field

生物高分子材料学

Academic Significance and Societal Importance of the Research Achievements

きのこ類に含まれるβ-1,6グルカンは免疫活性化機能を持つ。しかしながら、きのこ類からの単離・精製は困難であるため、純粋なβ-1,6グルカンが得られた例はない。β-1,6グルカンは生物の中で真菌類のみが唯一所有する分子あり、ヒトはβ-1,6グルカンを真菌類を認識する際の目印としている可能性がある。近年、食用きのこの大量栽培が可能になってきたが、消費量は伸び悩んでいる。本研究によってβ-1,6グルカンを、免疫に関与する新しい機能性食物繊維として提唱できれば、きのこ類に新たな価値を生み出すことができ、きのこ産業の活性化に繋がる。