Investigation of chetomin as a lead compound and its biosynthetic pathway

• Published in: Applied microbiology and biotechnology Vol. 106; no. 8; pp. 3093 - 3102
• Main Authors: Zhao, Peipei, Liu, Hairong, Wu, Qinghua, Meng, Qingzhou, Qu, Kunyu, Yin, Xin, Wang, Mengmeng, Zhao, Xiangxiang, Qi, Jun, Meng, Yiwei, Xia, Xuekui, Zhang, Lixin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2022; Springer; Springer Nature B.V
• Subjects: Analysis; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Applied Genetics and Molecular Biotechnology; Bioactive compounds; Biological activity; Biomedical and Life Sciences; Biosynthesis; Biosynthetic Pathways - genetics; Biotechnology; Chaetomium; Disulfides; DNA sequencing; Drug resistance; Enzymes; Fungi; Gene clusters; Gene expression; Gene sequencing; Genetic aspects; Genomes; Genomics; Glutathione; Glutathione transferase; Identification and classification; Indole Alkaloids; Lead; Lead compounds; Life Sciences; Metabolites; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Genetics and Genomics; Microbiology; Minimum inhibitory concentration; Nucleotide sequencing; Properties; Proteome; Proteomes; Staphylococcus aureus; Staphylococcus infections; Transcriptomes; Vancomycin; China; Chetomin; Gene cluster; Anti-MRSA; Proteome; Heterologous expression; Chaetomium
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-022-11925-y

Chaetomium fungi produce a diversity of bioactive compounds. Chaetomium cochliodes SD-280 possesses 91 secondary metabolite gene clusters and exhibits strong antibacterial activity. One of the active compounds responsible for that activity, chetomin, has a minimum inhibitory concentration (MIC) for anti-methicillin-resistant Staphylococcus aureus (MRSA) of 0.05 μg/mL (vancomycin: 0.625 μg/mL). This study demonstrated that the addition of glutathione (GSH) can enhance chetomin yield dramatically, increasing its production 15.43-fold. Following genome sequencing, cluster prediction, and transcriptome and proteome analyses of the fungus were carried out. Furthermore, a relatively complete chetomin biosynthetic gene cluster was proposed, and the coding sequences were acquired. In the cluster of GSH-treated cells, proteome analysis revealed two up-regulated proteins that are critical enzymes for chetomin biosynthesis. One of these enzymes, a nonribosomal peptide synthetase (NRPS), was heterologously expressed in Aspergillus nidulans , and one of its metabolites was determined to be an intermediate in the chetomin biosynthetic pathway. We present here, to our knowledge, the first experimental evidence that chetomin exhibits strong bioactivity against MRSA. Our work also provides extensive insights into the biosynthetic pathway of chetomin, in particular identifying two key enzymes (glutathione S-transferase (CheG) and NRPS (CheP)) that substantially up-regulate chetomin. These mechanistic insights into chetomin biosynthesis will provide the foundation for further investigation into the anti-pathogenic properties and applications of chetomin. Key points • Chetomin exhibits strong anti-MRSA activity with MIC of 0.05 μg/mL . • Addition of glutathione improved the yield of chetomin by 15.43-fold . • CheG and CheP involved in the chetomin biosynthesis were revealed for the first time .