Majumder Anusha, Kanti Mondal Sunil, Mukhoty Samyabrata, Bag Sagar, Mondal Anupam, Begum Yasmin, Sharma Kalpna, Banik Avishek
Laboratory of Microbial Interaction, School of Biotechnology, Presidency University, Kolkata, West Bengal, India.
Department of Biotechnology, The University of Burdwan, Burdwan, West Bengal, India.
Food Chem X. 2022 Jan 18;13:100212. doi: 10.1016/j.fochx.2022.100212. eCollection 2022 Mar 30.
Flavour of tea is mainly contributed by a group of polyphenols - flavonoids. However, the content of flavonoid fluctuates seasonally and is found to be higher in the first flush of tea, when compared to the second flush. This disparity in the flavonoid content, and hence taste, incurs heavy economic losses to the tea plantation industry each harvest season. For our present study, four key product-specific enzymes (PAL, FNS, FLS and ANS) of the tea-specific flavonoid pathway were selected to perform molecular docking studies with specific virtually screened allosteric modulators. Results of docking analyses showed Naringenin, 2-Morpholin-4-ium-4-ylethanesulfonate, 6-C-Glucosylquercetin, 2-Oxoglutaric acid, 3,5,7,3',4'-pentahydroxyflavone to be capable of improving the spontaneity of the enzyme-substrate reactions in terms of docking score, RMSD values, and non-covalent interactions (H-bond,hydrophobic interaction, Π-stacking, salt bridge, etc.). Further, the evolutionary relationship of tea flavonoid pathway enzymes was constructed and compared with related taxa. The codon usage-based of tea flavonoid biosynthetic genes indicated the non-biasness of their nucleotide composition. Overall this study will provide a direction towards putative ligand-dependent enhancement of flavonoid content, irrespective of seasonal variation.
茶的风味主要由一组多酚类物质——类黄酮决定。然而，类黄酮的含量会随季节波动，并且发现与第二次采摘相比，在第一次采摘的茶叶中含量更高。类黄酮含量以及由此导致的口感差异，在每个收获季节给茶叶种植产业带来了巨大的经济损失。在我们目前的研究中，选择了茶特异性类黄酮途径的四种关键产物特异性酶（苯丙氨酸解氨酶、黄酮合酶、黄酮醇合酶和花青素合酶）与特定的虚拟筛选变构调节剂进行分子对接研究。对接分析结果表明，柚皮素、2-吗啉-4-基乙磺酸盐、6-C-葡萄糖基槲皮素、2-氧代戊二酸、3,5,7,3',4'-五羟基黄酮在对接分数、均方根偏差值和非共价相互作用（氢键、疏水相互作用、π堆积、盐桥等）方面能够提高酶-底物反应的自发性。此外，构建了茶类黄酮途径酶的进化关系并与相关分类群进行了比较。基于密码子使用情况的茶类黄酮生物合成基因表明其核苷酸组成没有偏向性。总体而言，这项研究将为无论季节变化如何，通过假定配体依赖方式提高类黄酮含量提供一个方向。
