Plant Molecular Biology Unit, Biochemical Sciences Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana 121001, India.
Int J Biol Macromol. 2021 Jun 30;181:202-210. doi: 10.1016/j.ijbiomac.2021.03.129. Epub 2021 Mar 24.
Plant 4-coumarate-CoA ligase (4CL) catalyzes the ligation of CoA to cinnamic acid and its derivatives. Activated CoA esters are utilized for the biosynthesis of phenolic metabolites and lignin that play essential function in plants. Here, we characterize the diversity of Ocimum kilimandscharicum 4CLs (Ok4CLs). Phylogenetic analysis suggest that Ok4CLs could be grouped into three classes, class I - enzymes mostly involved in lignin biosynthesis, class II - non-structural phenylpropanoid biosynthesis and class III - yet to be characterized for specific role(s). We selected two Ok4CLs namely Ok4CL7 and Ok4CL15 for further characterization. Gene expression analysis suggested that Ok4CL7 is highly expressed in leaf trichomes, whereas Ok4CL15 is abundant in the roots. The recombinant Ok4CL7 and Ok4CL15 had optimal enzyme activities at 40 °C in pH 8 and 7, respectively. Ok4CL7 showed substrate preference towards p-coumaric acid, ferulic acid and caffeic acid. While, Ok4CL15 preferred p-coumaric acid, ferulic acid and sinapic acid. Feruloyl adenylate showed higher number of contacts and lowers binding energy with Ok4CL7 and 15 compared to cinnamoyl adenylate. Based on root-specific expression and preference for sinapic acid, Ok4CL15 might be involved in lignin biosynthesis. Further exploration is needed to unravel the role of diverse Ok4CLs in O. kilimandscharicum.
植物 4-香豆酸辅酶 A 连接酶（4CL）催化 CoA 与肉桂酸及其衍生物的连接。激活的 CoA 酯被用于酚类代谢物和木质素的生物合成，这些物质在植物中发挥着重要作用。在这里，我们对罗勒 4-香豆酸辅酶 A 连接酶（Ok4CLs）的多样性进行了表征。系统发育分析表明，Ok4CLs 可分为三类，I 类——主要参与木质素生物合成的酶，II 类——非结构苯丙烷生物合成，III 类——尚未确定其特定作用。我们选择了两个 Ok4CL，即 Ok4CL7 和 Ok4CL15 进行进一步的表征。基因表达分析表明，Ok4CL7 在叶表皮毛中高度表达，而 Ok4CL15 在根中含量丰富。重组的 Ok4CL7 和 Ok4CL15 的最适酶活分别在 pH8 和 7 下，40°C 时达到最佳。Ok4CL7 对 p-香豆酸、阿魏酸和咖啡酸表现出底物偏好。而 Ok4CL15 则更喜欢 p-香豆酸、阿魏酸和芥子酸。与肉桂酰腺嘌呤相比，阿魏酰腺嘌呤与 Ok4CL7 和 15 的接触次数更多，结合能更低。基于根特异性表达和对芥子酸的偏好，Ok4CL15 可能参与木质素的生物合成。需要进一步探索以揭示不同 Ok4CLs 在罗勒中的作用。
