Calcium Ion-Dependent Increase in Thermostability of Dextran Glucosidase from<i>Streptococcus mutans</i>

• KOBAYASHI Momoko

  Research Faculty of Agriculture, Hokkaido University

• HONDOH Hironori

  Research Faculty of Agriculture, Hokkaido University

• MORI Haruhide

  Research Faculty of Agriculture, Hokkaido University

• SABURI Wataru

  Research Faculty of Agriculture, Hokkaido University

• OKUYAMA Masayuki

  Research Faculty of Agriculture, Hokkaido University

• KIMURA Atsuo

  Research Faculty of Agriculture, Hokkaido University

書誌事項

タイトル別名

• Calcium Ion-Dependent Increase in Thermostability of Dextran Glucosidase from Streptococcus mutans

抄録

Dextran glucosidase from Streptococcus mutans (SmDG), which belongs to glycoside hydrolase family 13 (GH13), hydrolyzes the non-reducing terminal glucosidic linkage of isomaltooligosaccharides and dextran. Thermal deactivation of SmDG did not follow the single exponential decay but rather the two-step irreversible deactivation model, which involves an active intermediate having 39% specific activity. The presence of a low concentration of CaCl₂ increased the thermostability of SmDG, mainly due to a marked reduction in the rate constant of deactivation of the intermediate. The addition of MgCl₂ also enhanced thermostability, while KCl and NaCl were not effective. Therefore, divalent cations, particularly Ca²⁺, were considered to stabilize SmDG. On the other hand, CaCl₂ had no significant effect on catalytic reaction. The enhanced stability by Ca²⁺ was probably related to calcium binding in the β→α loop 1 of the (β⁄α)₈ barrel of SmDG. Because similar structures and sequences are widespread in GH13, these GH13 enzymes might have been stabilized by calcium ions.

収録刊行物

• Ｂｉｏｓｃｉｅｎｃｅ，　Ｂｉｏｔｅｃｈｎｏｌｏｇｙ，　ａｎｄ　Ｂｉｏｃｈｅｍｉｓｔｒｙ

  Ｂｉｏｓｃｉｅｎｃｅ，　Ｂｉｏｔｅｃｈｎｏｌｏｇｙ，　ａｎｄ　Ｂｉｏｃｈｅｍｉｓｔｒｙ 75 (8), 1557-1563, 2011

  公益社団法人 日本農芸化学会

キーワード

• dextran glucosidase
• thermostability
• two-step irreversible deactivation
• calcium-binding site
• glycoside hydrolase family 13

詳細情報

• CRID: 1390282681456572288
• NII論文ID: 10029591699
• NII書誌ID: AA10824164
• DOI: 10.1271/bbb.110256
• ISSN: 13476947
• ISSN: 09168451
• HANDLE: 2115/48146
• NDL書誌ID: 11222504
• PubMed: 21821929
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I11222504
• Web Site: http://www.tandfonline.com/doi/pdf/10.1271/bbb.110256
• 本文言語コード: en
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