ID 62132
著者
小博, 裕子 徳島大学
前田, 歩 徳島大学
香西, 美甫 徳島大学
杉山, 典子 徳島大学
福原, 健一 学習院大学
金井, 拓 徳島大学
武井, 俊朗 学習院大学|東京大学
三浦, 謹一郎 学習院大学|千葉工業大学|東京大学
キーワード
Inorganic pyrophosphatase
Thermal aggregation
Bulkiness Thermostability
Thermus thermophilus
資料タイプ
紀要論文
抄録
Thermus thermophilus Inorganic pyrophosphatase (Tth PPase) is comprised of homohexamer,and exhibits
high thermostability. However,the thermal aggregation containing the cross-linked dimer was observed after
heating above 85℃. Therefore,we focused on the sole cysteine (Cys168) in C-terminalregion,and evaluated the
effects of substitutions at this position on thermostability and thermal aggregation of Tth PPase.
Firstly,we prepared the four Cys168-substituted variants (C168A,L ,1,and F) by site-directed mutagenesis.
Although all variants formed hexamer in native state,C168A variant exhibited the highest thermostabilities for
the enzyme activity and quatemary structure in wild type and all variants,while the other variants decreased
them drastically as the side chain at the 168 position was much more bulky and hydrophobic in Tth PPase.
Moreover, suppression of thermal aggregation for C168A variant was observed in the ANS fluorescence
experiments. Therefore,we suggest that the small volume and less hydrophobicity of side chain at 168 position
may contribute to the conformational thermostability, and substitution with Ala is the most suitable for
thermostabilization and suppression ofthermal aggregation of Tth PPase.
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
75
終了ページ
84
並び順
75
発行日
2008-12-25
EDB ID
179285
フルテキストファイル
言語
eng
部局
理工学系