Department of Botany, Panjab University, Chandigarh, 160014, India.
Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, V6T1Z3, Canada.
Biochem Genet. 2024 Feb;62(1):413-435. doi: 10.1007/s10528-023-10428-3. Epub 2023 Jun 26.
The phenylalanine ammonia lyase (PAL) catalyses the first step of phenylpropanoid metabolic pathway which leads to the biosynthesis of a diverse group of secondary metabolites. Orchids serve as a rich source of metabolites and the availability of genome or transcriptome for selected orchid species provides an opportunity to analyse the PAL genes in orchids. In the present study, 21 PAL genes were characterized using bioinformatics tools in nine orchid species (Apostasia shenzhenica, Cypripedium formosanum, Dendrobium catenatum, Phalaenopsis aphrodite, Phalaenopsis bellina, Phalaenopsis equestris, Phalaenopsis lueddemanniana, Phalaenopsis modesta and Phalaenopsis schilleriana). Multiple sequence alignment confirmed the presence of PAL-specific conserved domains (N-terminal, MIO, core, shielding and C-terminal domain). All these proteins were predicted to be hydrophobic in nature and to have cytoplasmic localisation. Structural modelling depicted the presence of alpha helices, extended strands, beta turns and random coils in their structure. Ala-Ser-Gly triad known for substrate binding and catalysis of MIO-domain was found to be completely conserved in all the proteins. Phylogenetic study showed that the PALs of pteridophytes, gymnosperms and angiosperms clustered together in separate clades. Expression profiling showed tissue-specific expression for all the 21 PAL genes in the various reproductive and vegetative tissues which suggested their diverse role in growth and development. This study provides insights to the molecular characterization of PAL genes which may help in developing biotechnological strategies to enhance the synthesis of phenylpropanoids in orchids and other heterologous systems for pharmaceutical applications.
苯丙氨酸解氨酶（PAL）催化苯丙烷代谢途径的第一步，导致一组不同的次生代谢物的生物合成。兰花是代谢物的丰富来源，选定兰花物种的基因组或转录组的可用性为分析兰花中的 PAL 基因提供了机会。在本研究中，使用生物信息学工具在 9 种兰花物种（深裂石斛、台湾蝴蝶兰、串珠石斛、蝴蝶兰、文心兰、硬叶兜兰、硬叶兜兰、斑舌兰和香荚兰）中鉴定了 21 个 PAL 基因。多序列比对证实了 PAL 特异性保守结构域（N 端、MIO、核心、屏蔽和 C 端结构域）的存在。所有这些蛋白质都被预测为疏水性，具有细胞质定位。结构建模描述了它们结构中存在的α螺旋、延伸链、β转角和无规卷曲。在所有蛋白质中都发现了 Ala-Ser-Gly 三肽，该三肽已知可结合底物并催化 MIO 结构域。系统发育研究表明，蕨类植物、裸子植物和被子植物的 PAL 聚集在不同的分支中。表达谱显示，21 个 PAL 基因在各种生殖和营养组织中均表现出组织特异性表达，这表明它们在生长和发育中具有多种功能。本研究为 PAL 基因的分子特征提供了深入了解，这可能有助于开发生物技术策略，以提高兰花和其他异源系统中苯丙烷类化合物的合成，用于药物应用。
