红茶加工过程中:茉莉酸羧甲基转移酶功能研究

Molecular and Biochemical Characterization of Jasmonic Acid Carboxyl Methyltransferase Involved in Aroma Compound Production of Methyl Jasmonate during Black Tea Processing

第一作者

Jing Zhang

第一单位

安农大

通讯作者

Wei-Wei Deng

Abstract

背景+问题:MeJA, a volatile organic compound, is a principal flowery aromatic compound in tea. During the processing of black tea, MeJA is produced by JMT of the JA substrate, forming a specific floral fragrance. The biosynthesis of MeJA in tea plants, especially in tea processing, has not been reported.

主要研究:CsJMT was cloned from the leaves of tea plant, and the function of the encoded protein (CsJMT) was characterized by the prokaryotic expression system (using Escherichia coli)..

结果1:CsJMT was cloned from tea leaves; the three-dimensional structure of CsJMT was predicted. Enzyme activity was identified, and protein purification was investigated. Site-directed deletions revealed that N-10, S-22, and Q-25 residues in the beginning amino acids played a key functional role in enzyme activity.

结果2:The expression patterns of CsJMT in tea organs differed; the highest expression of CsJMT was observed in the fermentation process of black tea.

结论:These results aid in further understanding the synthesis of MeJA during black tea processing, which is crucial for improving black tea quality using specific fragrances and could be applied to the aromatic compound regulation and tea breeding improvement in further studies.

摘  要

茉莉酸甲酯(MeJA)是一种挥发性有机化合物,是茶中的主要花香型芳香化合物。在红茶加工过程中,茉莉酸(JA)底物的茉莉酸羧基甲基转移酶(JMT)产生MeJA,形成特定的花香。 CsJMT是从茶叶中克隆得到的。预测了CsJMT的三维结构。鉴定酶活性,并研究蛋白质纯化。定点删除显示起始氨基酸中的N-10,S-22和Q-25残基在酶活性中起关键功能作用。茶树器官中CsJMT的表达方式不同。在红茶的发酵过程中,CsJMT的表达最高。这些结果有助于进一步理解红茶加工过程中MeJA的合成,这对于使用特定的香料改善红茶质量至关重要,并且可以用于进一步研究中的芳香族化合物调节和茶品系改良。

DOI:https://doi.org/10.1021/acs.jafc.0c06248

Journal: Journal of Agricultural and Food Chemistry

Impact Factor:4.192

Published date: Feb 18, 2021

END

三月

6

科学技术史上的今天

1521年3月6日,葡萄牙著名航海家麦哲伦率船队进行环球航行,到达太平洋西部的马里亚纳群岛。

1787年3月6日,德国物理学家夫琅和费诞生。夫琅和费从一个光学研究所的工人成为该所的负责人,曾自己设计制造了许多光学仪器,如消色差透镜、大型折射望远镜、衍射光栅等,在当时的物理界都是非常了不起的成果。夫琅和费最具影响力的贡献是发现并研究了太阳光谱中,即夫琅和费线。

1919年3月6日,英国物理学家豪森尔德出生。豪森尔德领导设计小组制造成功了英国第一台晶体管电子计算机,又完成了电子计算机控制的轴向 X射线断层照相的基本设想。1972年,豪森尔德在首次临床实验中应用 X射线断层照相扫描技术取得成功,为此他与科马克共同获得1979年诺贝尔生理学和医学奖。

Where there is a will, there is a way!

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