Identification and Manipulation of the Caprazamycin Gene Cluster Lead to New Simplified Liponucleoside Antibiotics and Give Insights into the Biosynthetic Pathway

Leonard Kaysser,Liane Lutsch,Stefanie Siebenberg,Emmanuel Wemakor,Bernd Kammerer,Bertolt Gust

doi:10.1074/jbc.m901258200

Leonard Kaysser, Liane Lutsch + Show 4 more

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https://doi.org/10.1074/jbc.m901258200

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Abstract

Caprazamycins are potent anti-mycobacterial liponucleoside antibiotics isolated from Streptomyces sp. MK730-62F2 and belong to the translocase I inhibitor family. Their complex structure is derived from 5'-(beta-O-aminoribosyl)-glycyluridine and comprises a unique N-methyldiazepanone ring. The biosynthetic gene cluster has been identified, cloned, and sequenced, representing the first gene cluster of a translocase I inhibitor. Sequence analysis revealed the presence of 23 open reading frames putatively involved in export, resistance, regulation, and biosynthesis of the caprazamycins. Heterologous expression of the gene cluster in Streptomyces coelicolor M512 led to the production of non-glycosylated bioactive caprazamycin derivatives. A set of gene deletions validated the boundaries of the cluster and inactivation of cpz21 resulted in the accumulation of novel simplified liponucleoside antibiotics that lack the 3-methylglutaryl moiety. Therefore, Cpz21 is assigned to act as an acyltransferase in caprazamycin biosynthesis. In vivo and in silico analysis of the caprazamycin biosynthetic gene cluster allows a first proposal of the biosynthetic pathway and provides insights into the biosynthesis of related uridyl-antibiotics.

Highlights

(6) [6] and the muraymycins [7] [7], which is cyclized to form a rare diazepanone ring
Chemical synthesis and biological activity of CPZs and LPMs has been studied in some detail, their biosynthesis remains speculative and only few data exists about the formation of other translocase I inhibitors [17, 18]
We assume that the CPZ biosynthetic pathway is partially similar to that of LPMs, FR-90043 [6], and muraymycins [7] and presents a model for the comprehension and manipulation of liponucleoside formation

Summary

Introduction

(6) [6] and the muraymycins [7] [7], which is cyclized to form a rare diazepanone ring. Heterologous expression of the gene cluster in Streptomyces coelicolor M512 led to the production of non-glycosylated bioactive caprazamycin derivatives. A total of 23 open reading frames, designated cpz9 –31, were assigned to the CPZ gene cluster putatively encoding for biosynthesis, resistance, transport, and regulatory functions (Fig. 2).

Results

Conclusion