The Biosynthesis of Capuramycin-type Antibiotics

Abstract

Background: Several nucleoside antibiotics contain a uridine-5Ј-carboxamide core of unclear origin. Results: The A-102395 biosynthetic gene cluster was cloned, a genetic system was developed, and three enzymes were characterized in vivo and in vitro. Conclusion: Uridine-5Ј-carboxamide originates from UMP and L-Thr by sequential reactions catalyzed by a dioxygenase and transaldolase. Significance: The results provide the first opportunity to methodically interrogate the biosynthesis of these unusual antibiotics.

Terfestatins B and C, New p-Terphenyl Glycosides Produced by Streptomyces sp. RM-5–8

“…RM-5–8 as containing a uniquely permissive glycosyltransferase of potential utility to chemoenzymatic glycodiversification efforts. 20 In addition, while the genes encoding metabolites bearing a C-2″-epimer of the corresponding unsaturated hexuronic acid (the 4,5-unsaturated-α- d -mannuronic acid within capuramycins) have recently been reported, 21 the biosynthetic pathway(s) for unsaturated hexuronic acid construction and/or attachment remain(s) uncharacterized. Furthermore, the demonstrated specific functional cytoprotection by 1 against EtOH toxicity in a primary brain cell culture model establishes, for the first time, the p -terphenyl scaffold as a neuroprotective agent within this context.…”

A biocatalytic approach to capuramycin analogues by exploiting a substrate permissive N-transacylase CapW

“…7-11,13,21 What was not known prior to this effort, however, was whether substituting for the l -ACL had any effect on the activity of the hexuronic acid phosphotransferase, which we previously established is a mechanism of self-resistance by the producing strain. 16,17 A similar phenomenon is found within aminoglycoside producing strains that often encode for phosphotransferases to covalently modify and inactivate the self-made antibacterial product, and it has been established that identical mechanisms—often acquired through horizontal gene transfer—are employed by pathogens to render these antibiotics inactive. 22 This resistance problem has been partially remedied by semisynthetic modification of an aminoglycoside at a distant site that prevents binding and catalysis by the covalently modifying enzyme.…”

“…4A) were previously shown to undergo enzymatic phosphorylation by CapP and the orthologous enzyme Cpr17, respectively, as a mechanism of self-resistance. 16,17 Both enzymes were also demonstrated to phosphorylate the noncognate capuramycin, suggesting lack of specificity regarding the l -ACL/polyamide component. 17 Several of the CapW-generated compounds were investigated as potential substrates for the phosphotransferase Cpr17.…”

“…16,17 Both enzymes were also demonstrated to phosphorylate the noncognate capuramycin, suggesting lack of specificity regarding the l -ACL/polyamide component. 17 Several of the CapW-generated compounds were investigated as potential substrates for the phosphotransferase Cpr17. All of the analogues where converted to a new product that yielded a mass consistent with the monophosphorylated product (Fig.…”

Mechanism of action of nucleoside antibacterial natural product antibiotics

“…The biosynthetic steps for attachment of a caprolactam moiety were elucidated, via carboxy methyltransferase CapS and transferase CapW[64]. The biosynthetic gene cluster for capuramycin A-102395 has also been reported, involving the incorporation of L-threonine into uridine 5'-carboxamide[65]. Transferase CapW has been used to prepare of a set of 43 semi-synthetic bioactive capuramycin derivatives[66].…”