The Effect of H133V of α-Amylase Bacillus licheniformis F11 in High Temperature using Molecular Dynamics Simulation

Abstract

Catalyst plays a central role in the chemical industry. In the starch processing industry, acid-based catalyst is used to degrade starch. Unfortunately, this catalyst is not environmentally friendly. Enzymes catalyzing the starch degradation are the alternative biological catalyst that reduces the potential risks caused by a conventional catalyst. Bacillus licheniformis α-amylase F11 (BLA F11), a locally sourced enzyme from Indonesia, has a great catalytic activity but is less tolerant at high temperatures is promising to be used. Ideally, industrial hydrolysis requires an enzyme with relatively stable at extreme temperatures (95-105˚C). To reach this condition, modification of the BLA F11 at the structural level is required to improve the thermal stability. Substitution at position 133 from valine to histidine was applied to the structure. This modification is expected to be stable at high temperatures. This study aimed to determine the effect of H133V on the structure of BLA F11 using molecular dynamics simulation. In this study, the structure of BLA F11 and its mutant was built using homology modeling and the structural behavior in high temperature was observed using molecular dynamic simulation. Bacillus licheniformis α-amylase (PDB code 1OB0) was used as a positive control because of thermostable. The results showed that the modification of H133V was predicted to have more hydrophobic interactions, which are associated with the positive control. This mutation also reduced the flexibility of the nearby loop and improved the secondary structure stability of β-sheet in the B domain which involved thermal stability.

Keywords: Molecular dynamics simulation, Bacillus licheniformis, thermostability, amylase