Actions of Tryptophan Prenyltransferases Toward Fumiquinazolines and their Potential Application for the Generation of Prenylated Derivatives by Combining Chemical and Chemoenzymatic Syntheses

Abstract

Abstract:D imethylallyltryptophan synthases (DMATSs) catalyze regiospecific transfer reactions of ap renylm oiety from dimethylallyl diphosphatet o various positions of the indole ring of tryptophan. Fore xample, FgaPT2, 5-DMATS,a nd 7-DMATS from Aspergillus fungi catalyze tryptophan prenylation at C-4, C-5, and C-7, while 5-DMATS Sc and6 -DMATS Sa from Streptomyces strains are tryptophan C-5 and C-6 prenyltransferases,r espectively.I nt his study,o ur objective is to demonstrate the possibility of producing prenylated analoguesofardeemin fumiquinazoline (FQ) (1a), ap recursoro ft he multidrug resistance (MDR)e xport pump inhibitora rdeemin, by using DMATSs.A ll ardeeminF Qs tereoisomers were chemically synthesizeda nd useda ss ubstrates for enzyme assays with DMATSs.B iochemical investigations revealeddifferent featuresofthese enzymes toward ardeemin FQ analogues,r egarding activity and prenylation position. Isolation and structural elucidations howedt hat 7-DMATS catalyzed mainly regiospecific prenylation at C-7, which is also observed for its natural substrate l-tryptophan. Up to four prenylated derivatives were identified in the reaction mixtureso fother enzymes.I nt otal, 18 new prenylated ardeeminF Qa nalogues were obtained in this study.M olecular modelling of ardeemin FQ analogues with the crystals tructure of FgaPT2 led to the identification of two potentiala mino acid residues for guidance of the prenylation position. The two generated mutants FgaPT2_M328L andF gaP-T2_Y398F showeds ignificant prenylation shifts with 1a.

FgaPT2, a biocatalytic tool for alkyl-diversification of indole natural products

“…Several studies have revealed that FgaPT2 has a broad and diverse acceptor substrate scope, including substituted tryptophan, l -Trp containing cyclic dipeptides, isomers of l -tyrosine, indolocarbazoles, and phenolic molecules 35–40. A few alternative alkyl donors have also been reported with FgaPT2 including the C 10 geranyl pyrophosphate (GPP), 2-butenyl pyrophosphate, 2-pentenyl pyrophosphate, and benzyl pyrophosphate 41,42.…”

Structural Basis of Tryptophan Reverse N-Prenylation Catalyzed by CymD

“…Members of the DMATS group are found in both bacteria and fungi, though their level of sequence identity is low. Characterizing the structural and enzymatic properties of members of the DMATS group has been an active area of investigation given their role in the biosynthesis of useful natural products. − There is currently a need for additional structural studies to better inform molecular modeling of this class of enzymes.…”

Regioselective Biocatalytic C4‐Prenylation of Unprotected Tryptophan Derivatives

“…It is worth to mention, that prenylation of C4‐substituted tryptophan analogues was reported in other positions with this type of enzyme on a 5 mL scale at 20 mM tryptophan/8.8 mM DMAPP [19] . During the last years, various DMATS have been investigated for the prenylation of several alternative substrates like fumiquinazolines [20] and tyrosines [21] …”