Discovery, Isolation, and Structure Elucidation of Dretamycin

Abstract

The Candida albicans fitness test is a whole cell screening platform that utilizes a mixed-pool of C. albicans mutants, each of which carries a heterozygous deletion of a particular gene. In the presence of an antifungal inhibitor, a subset of these mutants exhibits a growth phenotype of hypersensitivity or hyposensitivity. Collectively these mutants reflect aspects of the mechanism of action of the compound in question. In the course of screening natural products a culture of Streptomyces sp. MS-1-4 was discovered to produce a compound, dretamycin, which yielded a fitness profile exhibiting significant hypersensitivity of the DRE2 heterozygote and hyposensitivity of the DIP5 heterozygote. Herein we report the production, isolation, and structure elucidation of dretamycin.

The tricarboxylic acid cycle, cell wall integrity pathway, cytokinesis and intracellular pH homeostasis are involved in the sensitivity of Candida albicans cells to high levels of extracellular calcium

“…The GRACE (gene replacement and conditional expression) library of conditional mutants with one allele of a target gene deleted and the other placed under the control of a tetracycline-repressive promoter, provides a functional genomics tool that was successfully used to assess gene essentiality in C. albicans [Roemer et al 2003]. This library has been used for mechanism-of-action studies of various compounds against C. albicans as well as for studies on the role of essential genes with respect to pathogen virulence in a murine model of candidiasis [Wilson et al 2014;Becker et al 2010;Xu et al 2007]. In addition, a modified GRACE library (version 1) has been used to screen for genes involved in white-opaque switching that identified OFR1 as a key regulator for maintaining the cryptic mating phenotype in C. albicans [Sun et al 2016], and has also been used to study the interactions between genes and antifungal drugs [Chen et al 2018].…”

Campafungins: Inhibitors of Candida albicans and Cryptococcus neoformans Hyphal Growth

“…C NMR Spectrum of[1,[2][3][4][5][6][7][8][9][10][11][12][13] C 2 ]-Acetate-Labeled 1 Not observed due to overlap.…”

“…Testing of prescreened natural product extracts allowed the development of a straightforward, large-scale natural product screening strategy capable of detecting molecules effective against a broad array of known and novel targets. Application of this strategy with microbial natural products resulted in the discovery of the parnafungins, , inhibitors of mRNA processing, a previously undescribed antifungal target; natural product and synthetic inhibitors of the glycosylphosphatidylinositol (GPI) anchor pathway; inhibitors of elongation factor 3 (EF3), a fungal selective protein synthesis target; new analogues of inhibitors of more established antifungal targets; and several other new natural products for which the precise MOAs remain unresolved. − …”