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ID 62133
著者
田中, 浩史 徳島大学
前田, 歩 徳島大学
杉山, 典子 徳島大学
京極, 仁美 徳島大学
香西, 美甫 徳島大学
武井, 俊朗 千葉工業大学|東京大学
三浦, 謹一郎 千葉工業大学|東京大学
キーワード
Inorganic pyrophosphatase
Intertrimer interface
Site-directed mutagenesis
Thermostability
Thermus thermophilus
資料タイプ
紀要論文
抄録
Inorganic pyrophosphatase (EC. 3.6.1.1) from Thermus thermophilus (Tth PPase)is a thermostable
homohexamer of 174 amino acids,and its intertrimer interface is formed mainly by the symmetric α-helix A
between subunits. Amino acids and their interactions composing intertrimer interface are different in hexameric
Family I PPases,and then it was deduced that Tth PPase showed high thermostability because of stabilizing this
interface by interactions of these residues. In this study,we focused on Thr138 and Ala141 residues in intertrimer
interface of Tth PPase to confirm the relationship between intertrimeric residues and thermostability, and then
improved their combination to His and Asp/Glu (HD or HE variant).
As results,the HD variant showed the highest thermostability of enzyme activity,fluorescence spectra, and
quaternary structure in the wild type Tth PPase and all variants. Especially,about 38% of hexamer and almost
40% of enzyme activity were observed in HD variant after heating even at 85℃. Therefore,we suggested that
the conversion to a set of ionic His138 and Asp141 at intertrimer interface had increased the thermostability of
Tth PPase,and then suppressed its thermal aggregation.
掲載誌名
徳島大学総合科学部自然科学研究 = Natural Science Research, The University of Tokushima
ISSN
09146385
cat書誌ID
AN10065859
出版者
徳島大学総合科学部
22
開始ページ
85
終了ページ
96
並び順
85
発行日
2008-12-25
EDB ID
フルテキストファイル
言語
eng
部局
理工学系