Improved Synthesis of Flavonoids by Simulation of Naringenin Chalcone Biosynthetic Reaction

Abstract

Metabolic Control Analysis provides a quantitative description of concentration dynamics with the change in system parameters. A metabolic Control Analysis aids determination of the threshold value of metabolites involved in a reaction and also helps to understand the role of various parameters in a reaction. In this work, a metabolic model of a Naringenine chalcone biosynthetic reaction is defined and a time series simulation was carried out based on the law of Mass action. Initial concentration of p-Coumaroyl-CoA and Malonyl-CoA were taken 5.0*10-2 mM 2.2*10-3 mM respectively. This concentration was then simulated over time for 10 seconds to find the steady state. Final concentration of  Naringenine chalcone,CO2, and CoA becomes 8.593946e-004 mM after 5.00 second of simulation at reaction constant 6.587753e-005 mM*ml/s. Steady state solution shows that Initial concentration of Naringenine chalcone was 2.199777e-003 mM which is eventually converted into 2.785128e+013 seconds half-life concentration of product at 7.898e-017 mM/s rate and  0.000000e+000 mM*ml/s  rate constant. Phenylpropanoid pathway was analysed to predict all the enzymes that can maximise and minimise the concentration of  Malonyl-CoA and P-Coumaroyl-CoA which leads to flavonoid biosynthesis. In the Phenylpropanoid pathway four enzymes Phenylalanine/tyrosine ammonia lyase, trans-cinnamate 4-monooxygenase, Phenylalanine ammonia lyase, maximise the flavonoid biosynthesis. This analysis shows that other enzymes minimise the concentrations of  Malonyl-CoA and P-coumaroyl-CoA, these are Cinnamoyl Co A reductase, shikimate O hydroxyl transferase HCT), Oxidoreductase. Furthermore, Protein domain analysis of chalcone synthase mutants ( 1jwx Medicago sativa and 4yjy from Oryza sativa) was done to predict structural features to understand reaction mechanism and structure-based engineering to maximise flavonoid biosynthesis. Natural sequence variation CHS G256A, G256V, G256L, and G256F mutants of residue 256 reduce the size of the active site cavity but quick diversification of product specificity occurs. The threshold concentration of Malonyl-CoA and P-coumaroyl-CoA were predicted, maximisation of this concentration leads to enhanced flavonoid biosynthesis. Inhibition of few enzymes may also maximise the flavonoid biosynthesis if appropriate inhibitors are used and a constant supply of Malonyl-CoA and P-Coumaroyl-CoA is maintained using activator molecules. Chalcone synthase Mutants diversify product specificity that occurs without loss of catalytic activity and any conformational changes.