C7-Prenylation of Tryptophan-Containing Cyclic Dipeptides by 7-Dimethylallyl Tryptophan Synthase Significantly Increases the Anticancer and Antimicrobial Activities

Abstract

Prenylated natural products have interesting pharmacological properties and prenylation reactions play crucial roles in controlling the activities of biomolecules. They are difficult to synthesize chemically, but enzymatic synthesis production is a desirable pathway. Cyclic dipeptide prenyltransferase catalyzes the regioselective Friedel–Crafts alkylation of tryptophan-containing cyclic dipeptides. This class of enzymes, which belongs to the dimethylallyl tryptophan synthase superfamily, is known to be flexible to aromatic prenyl receptors, while mostly retaining its typical regioselectivity. In this study, seven tryptophan-containing cyclic dipeptides 1a–7a were converted to their C7-regularly prenylated derivatives 1b–7b in the presence of dimethylallyl diphosphate (DMAPP) by using the purified 7-dimethylallyl tryptophan synthase (7-DMATS) as catalyst. The HPLC analysis of the incubation mixture and the NMR analysis of the separated products showed that the stereochemical structure of the substrate had a great influence on their acceptance by 7-DMATS. Determination of the kinetic parameters proved that cyclo-l-Trp–Gly (1a) consisting of a tryptophanyl and glycine was accepted as the best substrate with a KM value of 169.7 μM and a turnover number of 0.1307 s−1. Furthermore, docking studies simulated the prenyl transfer reaction of 7-DMATS and it could be concluded that the highest affinity between 7-DMATS and 1a. Preliminary results have been clearly shown that prenylation at C7 led to a significant increase of the anticancer and antimicrobial activities of the prenylated derivatives 1b–7b in all the activity test experiment, especially the prenylated product 4b.

Diprenylated cyclodipeptide production by changing the prenylation sequence of the nature’s synthetic machinery

“…Comparison of the NMR data of 3 and 6 with those published previously proved their structures to be C4-and C7-prenylated derivatives, respectively (Fig. 4) (Liu et al 2020;Steffan and Li 2009).…”

“…Diprenylated products, e.g., tardioxopiperazines A and B, were only detected as minor products. Furthermore, the tryptophan C6 -prenyltransferase from Streptomyces ambofaciens and 7-DMATS from Aspergillus fumigatus can also prenylate CDPs at positions C-6 and C-7, respectively (Kremer et al 2007 ; Liu et al 2020 ; Winkelblech and Li 2014 ). In addition, protein engineering of the tryptophan C4 -prenyltransferase from Aspergillus fumigatus led to the mutant FgaPT2_R244L with increased acceptance for CDPs (Fan and Li 2016 ).…”

Structural insights into the diverse prenylating capabilities of DMATS prenyltransferases

“…Their unusually broad substrate scopes (Table 1), established utility in gaining access to hard-tomodify positions of NP scaffolds, and regio-and stereoselective chemistries have made DMATSs attractive candidates as biocatalysts for late-stage derivatization of several structurally diverse aromatic scaffolds. 24,25,65,67,69,86,88,89 Furthermore, as prenylation is oen a precursor to scaffold modications such as spirocyclization in vivo, it is also feasible to consider the use of DMATSs in biologically inspired synthetic workows. 41,[90][91][92] Prenylation is known to favorably modulate bioactivities, and prenylated aromatic NPs possess a wide range of desirable bioactivities, making DMATSs potential tools for use in drug discovery efforts.…”

“…Chemoenzymatic methods are practical alternatives to traditional synthetic means of derivatization, as enzyme-catalyzed reactions are environmentally friendly, safe to handle, take place under milder conditions without the need for protecting groups, and provide a level of regio- and stereoselectivity that traditional synthetic methods cannot match. 24,41,86,87 DMATSs are uniquely suited for applications in the chemoenzymatic synthesis of NP derivatives. Their unusually broad substrate scopes (Table 1), established utility in gaining access to hard-to-modify positions of NP scaffolds, and regio- and stereoselective chemistries have made DMATSs attractive candidates as biocatalysts for late-stage derivatization of several structurally diverse aromatic scaffolds.…”

A Single Amino Acid Switch Alters the Prenyl Donor Specificity of a Fungal Aromatic Prenyltransferase toward Biflavonoids

“…Biflavonoids, dimers of flavonoid moieties, are rich in structural diversity and pharmacological properties. , For example, amentoflavone ( 1 ), a well-known natural biflavonoid isolated from many plants such as Ginkgo biloba and Hypericum perforatum, possesses multiple bioactivities including antioxidant, anti-inflammatory, antitumor, antivirus, and antifungal effects. , Prenylation is an important diversification that is widely found in various types of natural products and it generally increases the bioactivity due to better affinity toward the cell membrane or target protein. − However, prenylated biflavonoids are rarely discovered in nature, which is in sharp contrast to the structural diversity of biflavonoids . Precise synthesis of prenylated biflavonoids is often difficult to accomplish due to poor chemoselectivity of regular chemical methods.…”