金属离子诱导类黄酮 prenyltransferase AhPT1 的底物特异性变化。
Substrate specificity change of a flavonoid prenyltransferase AhPT1 induced by metal ion.
机构信息
Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou 510650, China.
出版信息
Int J Biol Macromol. 2020 Jun 15;153:264-275. doi: 10.1016/j.ijbiomac.2020.03.005. Epub 2020 Mar 3.
Prenylated flavonoids are good drug candidates due to multiple biological activities and health benefits. Prenyltransferase is an important enzyme involved in the biosynthesis of prenylated flavonoids. In this work, a flavonoid prenyltransferase (AhPT1) from Artocarpus heterophyllus showed an unexpectedly metal ion-induced specificity to flavonoid substrates. AhPT1 could catalyse 6-C-prenylation of genistein when Mg serving as cofactor. Its catalytic activity to 6-hydroxyflavone was undetectable. However, when Mn was used instead of Mg, 5-C-prenylated 6-hydroxyflavone was generated with a high conversion rate. Mn altered the regiospecificity of AhPT1 and turned it into a 5-C-prenyltransferase. 2'-Hydroxyl could improve the conversion rate of 6-hydroxyflavone, whereas 3'- or 4'-hydroxyl impaired the catalysis efficiency of AhPT1. NQIFDADID174 and DLTDVEGD305 were active motifs involved in substrate binding and catalysis. Asn166, Asp170, Asp174, Asp298, Asp301 and Asp305 in the active center were critical to the prenylation reaction.
类黄酮prenyltransferases 是一类重要的酶，参与类黄酮化合物的生物合成。本研究从山竹中克隆到一个类黄酮prenyltransferase（AhPT1），它对金属离子具有意想不到的底物特异性。当镁作为辅助因子时，AhPT1 可以催化染料木黄酮的 6-C-prenylation；而当锰取代镁时，AhPT1 可以催化 6-羟基黄酮的 5-C-prenylation，生成高转化率的 5-C-prenylated 6-hydroxyflavone。锰离子改变了 AhPT1 的区域选择性，使其成为一个 5-C-prenyltransferase。2'-羟基可以提高 6-羟基黄酮的转化率，而 3'-或 4'-羟基则会损害 AhPT1 的催化效率。NQIFDADID174 和 DLTDVEGD305 是参与底物结合和催化的活性基序。活性中心的 Asn166、Asp170、Asp174、Asp298、Asp301 和 Asp305 对 prenylation 反应至关重要。
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