Molecular and structural characterization of a promiscuous chalcone synthase from the fern species Stenoloma chusanum  

作　　者：Rong Ni Meng Niu Jie Fu Hui Tan Ting‐Ting Zhu Jing Zhang Hong‐Xiang Lou Peng Zhang Jian‐Xu Li Ai‐Xia Cheng 

机构地区：[1]Key Laboratory of Chemical Biology of Natural Products,Ministry of Education,School of Pharmaceutical Sciences,Shandong University,Jinan 250100,China [2]National Key Laboratory of Plant Molecular Genetics,Center for Excellence in Molecular Plant Sciences,Shanghai Institute of Plant Physiology and Ecology,Chinese Academy of Sciences,Shanghai 200032,China

出　　处：《Journal of Integrative Plant Biology》2022年第10期1935-1951,共17页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 31770330 and 31870720);supported by the Foundation of Youth Innovation Promotion Association of the Chinese Academy of Sciences

摘　　要：The key enzymes involved in the flavonoid biosynthesis pathway have been extensively studied in seed plants,but relatively less in ferns.In this study,two 4-Coumarate:coenzyme A ligases(Sc4CL1 and Sc4CL2)and one novel chalcone synthase(ScCHS1)were functionally characterized by mining the Stenoloma chusanum transcriptome database.Recombinant Sc4CLs were able to esterify various hydroxycinnamic acids to corresponding acyl-coenzyme A(CoA).ScCHS1could catalyze p-coumaroyl-CoA,cinnamoyl-CoA,caffeoyl-CoA,and feruloyl-CoA to form naringenin,pinocembrin,eriodictyol,and homoeriodictyol,respectively.Moreover,enzymatic kinetics studies revealed that the optimal substrates of ScCHS1were feruloyl-CoA and caffeoyl-CoA,rather than p-coumaroyl-CoA,which was substantially different from the common CHSs.Crystallographic and sitedirected mutagenesis experiments indicated that the amino acid residues,Leu87,Leu97,Met165,and Ile200,located in the substrate-binding pocket near the B-ring of products,could exert a significant impact on the unique catalytic activity of ScCHS1.Furthermore,overexpression of ScCHS1 in tt4 mutants could partially rescue the mutant phenotypes.Finally,ScCHS1 and Sc4CL1 were used to synthesize flavanones and flavones with multi-substituted hydroxyl and methoxyl B-ring in Escherichia coli,which can effectively eliminate the need for the cytochrome P450 hydroxylation/O-methyltransferase from simple phenylpropanoid acids.In summary,the identification of these important Stenoloma enzymes provides a springboard for the future production of various flavonoids in E.coli.

关 键 词：chalcone synthase 4-Coumarate:coenzyme A ligases homoeriodictyol microbial production Stenoloma chusanum structure elucidation 

分 类 号：Q946[生物学—植物学]