Isolation and functional characterization of hydroxycinnamoyltransferases from the liverworts Plagiochasma appendiculaturn and Marchantia paleacea
Isolation and functional characterization of hydroxycinnamoyltransferases from the liverworts Plagiochasma appendiculaturn and Marchantia paleacea
复制标题
地钱斜裂和古地钱中羟基肉桂酰转移酶的分离和功能表征
DOI：
10.1016/j.plaphy.2018.06.019
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发表时间：
2018
影响因子：
6.5
通讯作者：
Lou Hong-Xiang
中科院分区：
文献类型：
--
作者：
Wu Yi-Feng;Zhao Yu;Liu Xin-Yan;Gao Shuai;Cheng Ai-Xia;Lou Hong-Xiang
羟基肉桂酰-CoA莽草酸/奎尼酸羟基肉桂酰转移酶（HCT，EC：2.3.1.133）是维管植物中合成单木质醇的关键代谢切入点;然而，对地钱中的HCT知之甚少。在这里，分离和表征的HCT编码的两个苔类，Plagiochasma apaperulatum和地钱，进行了说明。这两种酶的序列具有BAHD家族成员的典型特征，除了存在一段在高等植物HCT中不存在的>100个残基。当两个基因的截短版本，这是为了澄清这些额外的残基的意义，进行了研究，很明显，全长和截短的基因产物具有相似的催化活性，并识别相同的底物在体外。它们在烟草中瞬时表达时能提高CGA（5-CQA）和4-CQA的总产量，在苔类植物中稳定表达时能积累木质素样物质，二者在体内的功能相当。MpHCT的结构模型表明，其活性位点与其底物的结合类似于拟南芥HCT。虽然截短形式的HCT沉积在核质中，但全长形式仅发生在细胞质中。结论是地钱产生代表在研究植物中木质素合成的进化的出发点的ebona fideHCT。
Hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT, EC: 2.3.1.133) is a key metabolic entry point for the synthesis of monolignols in vascular plants; however, little is known about HCT in liverworts. Here, the isolation and characterization of HCTs encoded by the two liverwort species,Plagiochasma appendiculatumand Marchantiapaleacea, are described. The sequences of the two enzymes harbor features typical of BAHD family members, except for the presence of a stretch of >100 residues that are not represented in higher plant HCTs. When truncated versions of both genes, which were constructed to clarify the significance of these extra residues, were investigated, it became apparent that the full-length and the truncated gene products shared similar catalytic activity and recognized the same substratesin vitro. They also functioned equivalentlyin vivoeither when transiently expressed in tobacco to cause a higher total production of CGA (5-CQA) and 4-CQA or stably expressed in liverworts to accumulate the lignin-like contents. A structural model of MpHCT suggests that its active site bind to its substrate similar to that of Arabidopsis thaliana HCT. While truncated forms of HCT were deposited in the nucleocytoplasm, the full-length versions occurred exclusively in the cytoplasm. The conclusion is that liverworts producebona fideHCTs that represent a point of departure in studying the evolution of lignin synthesis in plants.