A Biosynthetic Platform for Antimalarial Drug Discovery

Abstract

14Advances in synthetic biology have enabled production of a variety of compounds using 15 bacteria as a vehicle for complex compound biosynthesis. Violacein, a naturally occurring 16 indole pigment with antibiotic properties, can be biosynthetically engineered in Escherichia 17 coli expressing its non-native synthesis pathway. To explore whether this synthetic 18 biosynthesis platform could be used for drug discovery, here we have screened bacterially-19 derived violacein against the main causative agent of human malaria, Plasmodium 20 falciparum. We show the antiparasitic activity of bacterially-derived violacein against the P. 21 falciparum 3D7 laboratory reference strain as well as drug-sensitive and resistant patient 22 33 KEYWORDS 34 Violacein; drug discovery; synthetic biology; antimalarial 35 36 on July 8, 2020 by guest http://aac.asm.org/ Downloaded from

GenoChemetic Strategy for Derivatization of the Violacein Natural Product Scaffold

“…Recently, we have generated a wide range of violacein and deoxyviolacein analogues from E. coli cells that were expressing a synthetic violacein biosynthesis pathway vioABCDE with added substituted tryptophans, and these crude extracts were tested against the malarial parasite Plasmodium falciparum . 24 Because of the promiscuity of the enzymes involved in the biosynthesis of violacein, we rationalized that a combination of enzymes from closely related bisindole biosynthesis pathways could generate compatible tryptophan analogues, leading to other interesting new-to-nature analogues of violacein that might otherwise be difficult to synthesize. Rebeccamycin is a closely related bisindole where the biosynthetic pathway contains several genes, including rebO (Q8KHS0) and rebD (Q8KHV6), which are homologous to vioA (Q9S3V1) and vioB (Q9S3V0), respectively.…”

“…We hypothesize that this is due to the preference of VioE in catalyzing the formation of 5′-Br-prodeoxyviolacein, in accordance with the isomer preference previously observed with various other violacein and deoxyviolacein analogues. 24 We then proceeded to screen a series of conditions that might facilitate Suzuki–Miyaura cross-coupling; however, because of low titers of 5′-bromo-violacein and 5′-bromo-deoxyviolacein available in the crude extract and challenges relating to the separation of these compounds that showed a propensity for pi-stacking, the isolation of products for further characterization and bioassays of the cross-coupling product proved difficult. We thus focused on systemically identifying conditions that would allow direct cross-coupling in crude extracts, which identified the optimal conditions for derivatization.…”

Violacein-Induced Chaperone System Collapse Underlies Multistage Antiplasmodial Activity

“…A recent study showed that violacein induces aggregation of actin in Plasmodium without affecting actin polymerization. 70 The study suggests that violacein might be interacting with actin indirectly via actin binding partners or by disturbing actin folding pathway. We propose that violacein disrupts the Plasmodium foldosome, in which Hsp70 and Hsp90 are critical players for the survaillance of protein folding, trafficking, quality control, and degradation processes.…”

Systematic review on the application of machine learning to quantitative structure–activity relationship modeling against Plasmodium falciparum

“…It was found that the nature of substituents on the aromatic ring greatly influenced the antiprotozoal activity and further confirmed that the enzyme PfDHODH was the target of these compounds. Violacein, an indole pigment synthetically engineered from E. coli, was found to significantly affect the P. falciparum actin cytoskeleton [ 38 ]. Many traditional methods of antimalarial drug discovery such as optimization of existing therapy, analogue of existing therapy, drug resistance reversers and active compounds against new targets are known.…”