Activation and Characterization of Lanthomicins A–C by Promoter Engineering in Streptomyces chattanoogensis L10

Abstract

The emergence of drug resistance highlights the importance of new drug discovery. Microbial secondary metabolites encoded in biosynthetic gene clusters (BGCs) are a prolific source of drugs, whereas most of these BGCs are cryptic. Thus, taking strategies to activate these cryptic BGCs is of great importance for potential drug discovery. In this work, three novel pentangular polyphenols lanthomicin A–C were identified by activating a cryptic aromatic polyketide BGC through promoter engineering combined with optimization of fermentation conditions. We further confirmed the involvement of lanthomicin (ltm) BGC in biosynthesis by CRISPR-Cpf1-assisted gene editing. Based on functional analysis of homologous genes, a putative biosynthetic pathway was proposed for the three lanthomicins. Particularly, lanthomicin A showed antiproliferative activity with IC50 0.17 μM for lung cancer cell line A-549. The discovery of lanthomicins brings new members to the pentangular polyphenol subclade of aromatic polyketide and demonstrates the potential of Streptomyces as a source for drug discovery.

Metabolic perturbation of Streptomyces albulus by introducing NADP-dependent glyceraldehyde 3-phosphate dehydrogenase

“…However, the majority of these BGCs, are silent when tested under standard laboratory conditions ( Liu et al, 2021 ). Therefore, numerous strategies, including heterologous expression ( Kang and Kim, 2021 ), overexpression in native host ( Li H. et al, 2022 ), promoter engineering ( Liu X. F. et al, 2022 ), transcriptional regulation engineering ( Li et al, 2019 ; Martínez-Burgo et al, 2019 ) and ribosome engineering ( Zhang et al, 2019 ; Li et al, 2021 ) have been developed to activate these BGCs in NP discovery studies ( Beck et al, 2021 ; Liu et al, 2021 ). However, since most of these studies focused on one or more metabolites, the full potential of Streptomyces has rarely been studied.…”

The Potential Use of Fungal Co-Culture Strategy for Discovery of New Secondary Metabolites

“…Therefore, the number of new fungal SMs by traditional axenic culture method has been greatly decreasing in the past two decades despite great progress made in chemical analysis and separation techniques. Fortunately, several approaches have been successfully developed and implemented for interrogating these silent BGCs and enhancing chemical diversity of fungal SM, such as one strain many compounds (OSMAC) strategy [ 12 , 13 , 14 ], heterologous expression technique [ 15 , 16 , 17 , 18 , 19 ], promoter engineering approach [ 20 , 21 , 22 , 23 ], and other genetic engineering methods [ 24 , 25 , 26 , 27 , 28 ]. A growing number of studies suggest that microbial co-culture has a greater effect not only on microbe growth but also on metabolism than axenic culture [ 11 , 29 ].…”