Alcohol-induced structural transitions in the acid-denatured Bacillus licheniformis alpha-amylase

作者：Abd Halim Adyani Azizah; Zaroog Mohammed Suleiman; Kadir Habsah Abdul; Tayyab Saad^*

来源：Journal of Saudi Chemical Society, 2017, 21: S349-S358.

DOI：10.1016/j.jscs.2014.04.002

• Acid-denatured state
• Alcohol-induced states
• Bacillus licheniformis alpha-amylase
• Structural transition
• Thermal denaturation

Alcohol-induced structural changes in the acid-denatured Bacillus licheniformis a-amylase (BLA) at pH 2.0 were studied by far-ultra violet circular dichroism, intrinsic, three-dimensional and 8-anilino-1-naphthalene sulfonic acid (ANS) fluorescence, acrylamide quenching and thermal denaturation. All the alcohols used in this study produced partial refolding in the acid-denatured BLA as evident from the increased mean residue ellipticity at 222 nm, increased intrinsic fluorescence and decreased ANS fluorescence. The order of effectiveness of these alcohols to induce a partially folded state of BLA was found to be: 2,2,2-trifluoroethanol/tert-butanol > 1-propanol/2-propanol > 2-chloroethanol > ethanol > methanol. Three-dimensional fluorescence and acrylamide quenching results obtained in the presence of 5.5 M tert-butanol also suggested formation of a partially folded state in the acid-denatured BLA. However, 5.5 M tert-butanol-induced state of BLA showed a non-cooperative thermal transition. All these results suggested formation of a partially folded state of the acid-denatured BLA in the presence of these alcohols. Furthermore, their effectiveness was found to be guided by their chain length, position of methyl groups and presence of the substituents.

• 出版日期2017-1