학술논문
Soluble Production, Characterization, and Structural Aesthetics of an Industrially Important Thermostable β-Glucosidase from Clostridium thermocellum in Escherichia coli.
Document Type
Article
Source
Subject
*CHROMATOGRAPHIC analysis
*CLOSTRIDIUM
*ESCHERICHIA coli
*GENE expression
*GENETIC techniques
*GLYCOSIDASES
*MOLECULAR structure
*SOLUBILITY
*DESCRIPTIVE statistics
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Language
ISSN
2314-6133
Abstract
This study aims to achieve high-level soluble expression and characterization of a thermostable industrially important enzyme, i.e., beta-glucosidase (BglA; EC: 3.2.1.21), from Clostridium thermocellum (C. thermocellum) by cloning in an Escherichia coli (E. coli) expression system. BglA was expressed as a partially soluble component of total cellular protein (TCP) having a molecular weight of ∼53 kDa with 50% of it as soluble fraction. Purification in two steps, namely, heat inactivation and Ni-chromatography, yielded approximately 30% and 15% of BglA, respectively. The purified (∼98%) BglA enzyme showed promising activity against the salicin substrate having a Km of 19.83 mM and a Vmax of 0.12 μmol/min. The enzyme had an optimal temperature and pH of 50°C and 7.0, respectively, while retaining its catalytic activity up till 60°C and at pH 7. The optimized maximum expression level was attained in M9NG medium with lactose as an inducer. Circular dichroism revealed presence of alpha helix (43.50%) and small percentage of beta sheets (10.60%). Factors like high-end cellulolytic activity, fair thermal stability, stability against low pH, and ease of purification make BglA from C. thermocellum a potential candidate in industrial applications. [ABSTRACT FROM AUTHOR]