In vitro and in silico studies of chalcone synthase variant 2 in Boesenbergia rotunda and its substrate specificity

Authors : Ragaventhan SANMUGAVELAN, Teow Chong TEOH, Nurnadiah ROSLAN, Zulqarnain MOHAMED

Pages : 213-223

View : 14 | Download : 3

Publication Date : 2018-12-01

Article Type : Research Paper

Abstract :  In this study, transformation of BrCHS var 2 into B. rotunda cell suspension culture, followed by chalcone synthase enzymatic assay and HPLC analysis was conducted to investigate whether the substrate specificity for BrCHS var 2 is either cinnamoyl-CoA or p -coumaroyl-CoA. The HPLC profile showed an increase in the amount of pinocembrin chalcone when cinnamoyl-CoA and malonyl-CoA were added but not p -coumaroyl-CoA. Molecular docking was performed to explore the binding of cinnamoyl-CoA and p -coumaroyl-CoA to BrCHS var 2 receptor and the docking results showed that cinnamoyl-CoA formed numerous hydrogen bonds and more negative docked energy than p -coumaroyl-CoA. Cinnamoyl-CoA showed good interactions with Cys 164 to initiate the subsequent formation of pinocembrin chalcone, whereas the hydroxyl group of p -coumaroyl-CoA formed an unfavorable interaction with Gln 161 that caused steric hindrance to subsequent formation of naringenin chalcone. Docked conformation analysis results also showed that malonyl-CoA formed hydrogen bonding with Cys 164, His 303, and Asn 336 residues in BrCHS var 2. The results show that cinnamoyl-CoA is the preferred substrate for BrCHS var 2.
Keywords : Chalcone synthase, cell suspension culture, homology modelling, molecular docking