Spectroscopic Analysis of Chloride Ion-induced Structural Change of Bacillus Amyloliquefaciens α-Amylase

Publication date: October 2019Source: Chinese Journal of Analytical Chemistry, Volume 47, Issue 10Author(s): Ning HAN, Zeng-Kuan ZHANG, Yu-Hua LI, Wei WANG, Liu-Jiao BIANAbstractThe structural change of Bacillus amyloliquefaciens α-amylase (Ba α-amylase) induced by chloride ion was studied by fluorescence spectra, Fourier-transformation infrared (FT-IR) spectroscopy and circular dichroism (CD) spectroscopy. It was found that when chloride ion concentration was below 20.0 mM, the Ba α-amylase was activated by increasing chloride ion concentration; when chloride ion concentration was over 20.0 mM, the biological activity of Ba α-amylase was inhibited by increasing chloride ion concentration. The spectroscopic analyses illustrated that the change in Ba α-amylase biological activity was caused by the alteration in secondary structure of Ba α-amylase. When chloride ion showed activation effect to Ba α-amylase, part of the random coils in Ba α-amylase gradually transformed to α-helix and β-sheet with increasing chloride ion concentration and the Ba α-amylase transited from relatively disordered conformation to relatively ordered one. Whereas when chloride ion showed inhibition effect on the biological activity of Ba α-amylase, part of α-helix and β-sheet in Ba α-amylase gradually transformed to random coil with increasing chloride ion concentration and the Ba α-amylase went back from the relatively ordered conformation to the relatively disordered one. This work sho...
Source: Chinese Journal of Analytical Chemistry - Category: Chemistry Source Type: research