Targeted Discovery and Combinatorial Biosynthesis of Polycyclic Tetramate Macrolactam Combamides A–E

Abstract

Polycyclic tetramate macrolactams (PoTeMs) are a growing class of natural products with distinct structure and diverse biological activities. By promoter engineering and heterologous expression of the cryptic cbm gene cluster, four new PoTeMs, combamides A-E (1-4), were identified. Additionally, two new derivatives, combamides E (5) and F (6), were generated via combinatorial biosynthesis. Together, our findings provide a sound base for expanding the structure diversities of PoTeMs through genome mining and combinatorial biosynthesis.

Construction of a hybrid gene cluster to reveal coupled ring formation–hydroxylation in the biosynthesis of HSAF and analogues from Lysobacter enzymogenes

“…13 CbmB, a homologous enzyme of OX1/OX2, is also responsible for the second five-membered ring in combamides. 9 The genes for PKS-NRPS, OX3 and OX4 were placed under the control of promoter kasOp*, and the cbmB gene under the control of promoter ermEp* (Fig. S1 ‡), using a similar strategy as reported.…”

“…S1 ‡), using a similar strategy as reported. 9 The hybrid construct was introduced into two strains of Streptomyces, SR111 and S001, through conjugation with an intermediate E. coli strain that carried the expression construct. This resulted in two engineered strains, SR111-HSAF hybrid and S001-HSAF hybrid .…”

“…SPB78, 7 combamides from Streptomyces sp. S10, 9 and from the marine-derived Streptomyces pactum SCSIO 02999 (ref. 10) ( Fig.…”

Genome Mining of Marine-Derived Streptomyces sp. SCSIO 40010 Leads to Cytotoxic New Polycyclic Tetramate Macrolactams

“…It should be noted that a trans-orientation of H-10 and H-11 was assigned for 1, because of the obvious NOESY correlations of H-8/H-10, H10/H-12, and H-11/H-29b ( Figure 3). Previously, a trans-orientation of H-10 and H-11 was reported for pactamide A [20], aburatubolactam A (X-ray crystallography structure available [31]), combamide D [32], deOH alteramides, and lysobacterene B [33]. In the recently reported 5/5 type of PTMs umezawamides, the relative orientation of H-10 and H-11 was not determined [34].…”

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“…S10 by promoter engineering, followed by heterologous expression, has generated four new products, including combamide A 23. 19 Using combinatorial biosynthesis that involved variation of redox enzymes, two further analogues were also generated.…”