IN SILICO ANALYSIS OF THE KEY ENZYMES INVOLVED IN SYNTHESIS OF SECONDARY METABOLITES IN CAMELLIA SINENSIS

Abstract

Tea is one of the most popular beverages worldwide, native to Southeast Asia but currently cultivated in over 35 countries. Studies on its chemical composition reveal that polyphenol metabolites account for 25% to 35% of the total dry weight. Tea has many health benefits owing to secondary metabolites whose level of expression in various tea clones determine tea flavor. The flavor (taste and aroma) and the color of processed tea are used to assess its quality and therefore a detailed analysis of key enzymes involved in the synthesis of secondary metabolites is necessary. This study employed a computational approach in the analysis of these enzymes to gain insight into the mechanism of synthesis of these bioactive secondary metabolites. Biological databases were used to retrieve amino acid sequences of these key enzymes. Consensus conserved regions in these sequences were identified from highly identical homologs which were useful in modeling the enzymes' three dimensional structures. A total of 14 key enzymes were analyzed and pockets and cavities in their structures; hence the putative substrate binding sites determined, which gave insight into the enzymes-substrate as well as enzyme cofactor interactions. The preferred orientations of the interactions between substrates and/or co-factors with the enzymes were also simulated through molecular docking. Analysis of these enzymes revealed unique enzyme structures and very specific substrate and co-factor preference. This analysis offers a platform for optimization of selective expression of these key enzymes through gene expression assays that can potentially alter the quality yield of tea clones.