Structural insight of β-amylase from Bacillus spp.: An in silico investigation for a plausible explanation of thermostability

This is the authors' abstract. We don't add key points for this paper.

The exoenzyme β-amylase catalyses the breakdown of the α-1,4-glycosidic bond of starch and produces maltose. Thermostable β-amylase has been reported from Bacillus spp. To identify comparatively higher structural stability under the simulated conditions of β-amylase enzyme from the different Bacillus species, an in silico investigation has been performed. In this study, we examined the sequence and structures of β-amylase from species of Bacillus that are available in the database. All seven studied β-amylase proteins showed hydrophilic characteristics. Bacillus mycoides and Bacillus gaemokensis were found to be the top two species with the highest number of charged polar residues, whereas B. weihaiensis revealed the highest number of uncharged polar residues. The highest polarity was observed in β-amylase from B. weihaiensis . Through intra-protein interactions, B. cereus and B. gaemokensis showed the highest number of salt bridges. B. gaemokensis also formed the highest number of network aromatic-aromatic interactions. B. gaemokensis and B. pseudomycoides possess higher aromatic-sulfur interactions. B. weihaiensis formed multiple isolated interactions, while B. clarus formed higher network cation-pi interactions. From molecular dynamics simulation analysis, the β-amylase of B. gaemokensis and B. pseudomycoides showed lower RMSD and lower structural fluctuations, and were found to be comparatively stable structures among all. This in silico investigation aids in determining the most likely stable β-amylase and the rationale for its stability.