2007年6月
Thermodynamic effects of disulfide bond on thermal unfolding of the starch-binding domain of Aspergillus niger glucoamylase
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY
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- 巻
- 71
- 号
- 6
- 開始ページ
- 1535
- 終了ページ
- 1541
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1271/bbb.70098
- 出版者・発行元
- TAYLOR & FRANCIS LTD
The thermodynamic effects of the disulfide bond of the fragment protein of the starch-binding domain of Aspergillus niger glucoamylase was investigated by measuring the thermal unfolding of the wild-type protein and its two mutant forms, Cys3Gly/Cys98Gly and Cys3Ser/Cys98Ser. The circular dichroism spectra and the thermodynamic parameters of binding with beta-cyclodextrin at 25 degrees C suggested that the native structures of the three proteins are essentially the same. Differential scanning calorimetry of the thermal unfolding of the proteins showed that the unfolding temperature t(1/2) of the two mutant proteins decreased by about 10 degrees C as compared to the wild-type protein at pH 7.0. At t(1/2) of the wild-type protein (52.7 degrees C), the mutant proteins destabilized by about 10 kJ mol(-1) in terms of the Gibbs energy change. It was found that the mutant proteins were quite stabilized in terms of enthalpy, but that a higher entropy change overwhelmed the enthalpic effect, resulting in destabilization.
- リンク情報
- ID情報
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- DOI : 10.1271/bbb.70098
- ISSN : 0916-8451
- eISSN : 1347-6947
- PubMed ID : 17587686
- Web of Science ID : WOS:000247793300019