Cloning, Expression and Characterization of a Novel α-Amylase from Salinispora arenicola CNP193

Characterization of an Amylolytic Enzyme from Massilia timonae of the GH13_19 Subfamily with Mixed Maltogenic and CGTase Activity

This work reports the characterization of an amylolytic enzyme from the bacteria Massilia timonae CTI-57. A gene encoding this protein was expressed from the pTrcHis2B plasmid in Escherichia coli BL21 Star™ (DE3). The purified protein had 64 kDa, and its modeled structure showed a monomer with the conserved α-amylases structure composed of the domain A with the characteristic (β/α)₈-barrel, the small domain B, and the domain C with an antiparallel beta-sheet. Phylogenetic analysis demonstrated that the expressed protein belongs to the GH13_19 subfamily of glycoside hydrolases. The ions Ca²⁺, Mn²⁺, Na⁺, Mg²⁺, Mo⁶⁺, and K⁺ did activate the purified enzyme, while EDTA and the ions Fe²⁺, Hg²⁺, Zn²⁺, and Cu²⁺ were strong inhibitors. SDS was also a strong inhibitor. The enzyme's optimal pH and temperature were 7.0 and 45 °C, respectively, and its T_m was 62.2 °C. The K_M of the purified enzyme for starch was 13 mg/mL, and the V_max was 0.24 μmol of reducing sugars released per min. The characterized enzyme presented higher specificity for maltodextrin and starch and produced maltose as the main starch hydrolysis product. This is the first characterized maltose-forming amylolytic enzyme from the GH13_19 subfamily. The purified enzyme produced β-cyclodextrin from starch and maltodextrin and could be considered a cyclodextrin glucanotransferase (CGTase). This is the first report of a GH13_19 subfamily enzyme with CGTase activity.

In Silico Approaches to Reveal Structural Insights, Stability and Catalysis of Bacillus-Derived α-Amylases Prior to Advance Lab Experiments

[Formula: see text]-amylase is the most widely used Glycoside Hydrolase (GH) in industries for decades. It randomly cleaves the [Formula: see text]-D-(1, 4) glucosidic bonds of [Formula: see text]-polysaccharides (starch and glycogen) to release glucose and short-chain oligosaccharides. Substantial advances have taken place in research related to [Formula: see text]-amylases. However, bioinformatics study needs a little more exploration before conducting wet-lab experiments. We aimed to perform a comparative structure-function relationship study of 10 different Bacillus-derived [Formula: see text]-amylases using several computational biology tools. After aligning all the [Formula: see text]-amylases, 3D structures were made using the SWISS-MODEL. The accuracy and stability of the predicted models were validated via different web servers like Verify-3D, ERRAT, RMSD and ProSA. MolProbity and PROCHECK were used for mapping the residues in the most favored region of the Ramachandran plot. The Ramachandran plot reveals that [Formula: see text] of the amino acid residues of the selected [Formula: see text]-amylase genes lie within the favored region. Our findings suggest that all the [Formula: see text]-amylases were stable as per the validation results we got. The study has revealed clear and concise structural related aspects. This paper will encourage the researchers to include and prioritize in silico work of [Formula: see text]-amylase genes to obtain more accurate outcomes. As the output obtained in this study via in silico tools reveals the structural peculiarity and more about the catalytic domain impression, it highly recommends incorporating such studies for better results. This approach will save efforts, costs and time for researchers.

Amylases from thermophilic bacteria: structure and function relationship

Amylases hydrolyze starch to diverse products including dextrins and progressively smaller polymers of glucose units. Thermally stable amylases account for nearly 25% of the enzyme market. This review highlights the structural attributes of the α-amylases from thermophilic bacteria. Heterologous expression of amylases in suitable hosts is discussed in detail. Further, specific value maximization approaches, such as protein engineering and immobilization of the amylases are discussed in order to improve its suitability for varied applications on a commercial scale. The review also takes into account of the immobilization of the amylases on nanomaterials to increase the stability and reusability of the enzymes. The function-based metagenomics would provide opportunities for searching amylases with novel characteristics. The review is expected to explore novel amylases for future potential applications.

Expression and characterization of a novel organic solvent tolerant protease from Bacillus sphaericus DS11

Organic solvent-tolerant proteases have many applications in the synthesis of peptides. In this study, we have developed a low-cost and convenient method to produce highly concentrated organic solvent-tolerant protease. Organic solvent tolerant protease (OSP) gene from Bacillus sphaericus DS11 was cloned and expressed in Bacillus subtilis WB800. The optimum pH of the recombinant protease was 9.0. The optimum temperature of the recombinant protease was 40 °C. The recombinant protease was purified by ethanol with the yield of (87.33%). The yield of OSP enriched by ethanol was higher than that of by Ni-chelating affinity chromatography, which indicated that precipitation of the recombinant OSP with ethanol is a relatively low-cost and fast method for organic solvent -tolerant protease preparation. These results showed that this enzyme could be very useful in different industrial applications.