Verification of new mechanistic model of starch branching enzyme

• Project/Area Number: 15K18685
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Applied biochemistry
• Research Institution: Akita Prefectural University
• Principal Investigator: Suzuki Ryuichiro 秋田県立大学, 生物資源科学部, 助教 (70632397)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
• Keywords: 酵素学 / 構造生物学 / 澱粉 / 枝作り酵素 / 農芸化学 / シアノバクテリア / 触媒特異性 / 改変

Outline of Final Research Achievements

Branching enzyme (BE) catalyzes formation of branch points of glycogen and starch. Active site cleft (subsite) of BE has never been reported. In this study, crystal structures of BE1 from starch-producing cyanobacteria Cyanothece sp. ATCC 51142 in complex with linear maltooligosaccharides were determined. The crystal structures revealed the location of subsites and the presence of seven surface binding sites (SBSs). Importance of amino acid residues involved in sugar binding at subsites and SBSs in the crystal structures was confirmed by mutational analysis of the residues. In addition, our results suggest that two SBSs in the catalytic domain participate in binding of acceptor substrate. Based on these results, new detailed mechanistic model of BE reaction has been presented.

Academic Significance and Societal Importance of the Research Achievements

澱粉（炭水化物）は人類の主食であり、食品産業・各種工業分野へ応用利用されている。澱粉の構造（分岐パターン）と食味・物性には相関があるが、澱粉の構造を制御する仕組みには未解明の課題が多く残されている。原始的なシアノバクテリアと進化した陸上植物について、澱粉構造の制御メカニズムを解明して比べることは、学術的に重要であり興味深い。応用展開としては、構造を制御した新規澱粉素材の酵素合成技術の確立に向けた第一歩になると期待される。

Research Products

• [Journal Article] Bound substrate in the structure of cyanobacterial branching enzyme supports a new mechanistic model (2017)
  • Author(s): Hayashi M, Suzuki R, Colleoni C, Ball SG, Fujita N, Suzuki E
  • Journal Title: J Biol Chem Volume: 292 Issue: 13 Pages: 5465-5475
  • DOI: 10.1074/jbc.m116.755629
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Distribution of glucan-branching enzymes among prokaryotes (2016)
  • Author(s): Suzuki E, Suzuki R
  • Journal Title: Cell Mol Life Sci Volume: - Issue: 14 Pages: 2643-2660
  • DOI: 10.1007/s00018-016-2243-9
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Crystallization and crystallographic analysis of branching enzymes from Cyanothece sp. ATCC 51142. (2015)
  • Author(s): Mari Hayashi, Ryuichiro Suzuki, Christophe Colleoni, Steven G Ball, Naoko Fujita, Eiji Suzuki
  • Journal Title: Acta Crystallographica section F STRUCTURAL BIOLOGY COMMUNICATIONS Volume: 71 Issue: 8 Pages: 1109-1113
  • DOI: 10.1107/s2053230x1501198x
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 新規特性を有するシアノバクテリア由来枝切り酵素の構造機能解析 (2017)
  • Author(s): 木村友亮, 鈴木龍一郎, 佐々木柾秀, Christophe Colleoni, Steven G. Ball, 藤田直子, 鈴木英治
  • Organizer: 日本農芸化学会2017年度大会
  • Place of Presentation: 京都女子大学
  • Year and Date: 2017-03-17
• [Presentation] 新規特性を有する枝切り酵素の構造機能解析 (2016)
  • Author(s): 鈴木龍一郎, 木村友亮, Christophe Colleoni, Steven G. Ball, 藤田直子, 鈴木英治
  • Organizer: 日本応用糖質科学会平成２８年度大会
  • Place of Presentation: 福山大学
  • Year and Date: 2016-09-14
• [Presentation] 貯蔵多糖特性の異なるシアノバクテリア由来枝作り酵素および枝切り酵素の構造と機能 (2016)
  • Author(s): 鈴木龍一郎, 林真里, 黒木みほ, 木村友亮, 佐々木柾秀, 藤田直子, 鈴木英治
  • Organizer: 日本応用糖質科学会平成２８年度大会
  • Place of Presentation: 福山大学
  • Year and Date: 2016-09-14
• [Presentation] シアノバクテリアSynechocystis sp. PCC 6803グリコーゲン枝切り酵素多重変異株の特性 (2016)
  • Author(s): 後藤光寛, 齊藤健太, 鈴木龍一郎, 鈴木英治
  • Organizer: 東北植物学会第６回大会
  • Place of Presentation: 東北大学
• [Remarks] 多糖代謝酵素タンパク質の構造生物学
  • URL: http://www.dbp.akita-pu.ac.jp/~plant-physiol/naiyou6.html