Terpenoids can be found in almost all forms of life; however, the biosynthesis of bacterial terpenoids has not been intensively studied. This study reports the identification and functional characterization of the gene cluster CYP264B1-geoA from Sorangium cellulosum So ce56. Expression of the enzymes and synthesis of their products for NMR analysis and X-ray diffraction were carried out by employing an Escherichia coli whole-cell conversion system that provides the geoA substrate farnesyl pyrophosphate through simultaneous overexpression of the mevalonate pathway genes. The geoA product was identified as a novel sesquiterpene, and assigned NMR signals unambiguously proved that geoA is an (+)-eremophilene synthase. The very tight binding of (+)-eremophilene (∼0.40 μM), which is also available in S. cellulosum So ce56, and its oxidation by CYP264B1 suggest that the CYP264B1-geoA gene cluster is required for the biosynthesis of (+)-eremophilene derivatives.

The development of novel antimycobacterial agents against Mycobacterium tuberculosis (Mtb) is urgently required due to the appearance of multidrug resistance (MDR) combined with complicated long‐term treatment. CYP121 was shown to be a promising novel target for inhibition of mycobacterial growth. In this study, we describe the rational discovery of new CYP121 inhibitors by a systematic screening based on biophysical and microbiological methods. The best hits originating from only one structural class gave initial information about molecular motifs required for binding and activity. The initial screening procedure was followed by mode‐of‐action studies and further biological characterizations. The results demonstrate superior antimycobacterial efficacy and a decreased toxicity profile of our frontrunner compound relative to the reference compound econazole. Due to its low molecular weight, promising biological profile, and physicochemical properties, this compound is an excellent starting point for further rational optimization.

Sesquiterpenes are natural products derived from the common precursor farnesyl pyrophosphate (FPP) but are highly diverse in structure and function. Cytochrome P450 enzymes (P450s) exhibit the unique ability to introduce molecular oxygen into non-activated C-H bonds. In plant biosynthetic pathways, P450s commonly derivatize sesquiterpene hydrocarbons. However, the potential of bacterial P450s for terpene derivatization is still underinvestigated. This work compares the substrate specificities and regioselectivities of the sesquiterpene hydroxylases CYP260A1 and CYP264B1 from myxobacterium Sorangium cellulosum So ce56. Four tested substrate classes (eremophilanes, humulanes, caryophyllanes, and cedranes) were converted by both P450s. The achievable variety of oxidations is demonstrated on the model substrates (+)-nootkatone and zerumbone. Increasing the number of functionally investigated P450s, this study represents a step towards the selective derivatization of sesquiterpenes.

Since cytochromes P450 are external monooxygenases, available surrogate redox partners have been used to reconstitute the P450 activity. However, the effect of various ratios of P450s and the redox proteins have not been extensively studied so far, although different combinations of the redox partners have shown variations in substrate conversion. To address this issue, CYP260A1 was reconstituted with various ratios of adrenodoxin and adrenodoxin reductase to convert 11-deoxycorticosterone, and the products were characterized by NMR. We show the effect of the available redox protein ratios not only on the P450 catalytic activity but also on the product pattern.

The myxobacterium Sorangium cellulosum So ce56 is a prolific producer of volatile sesquiterpenes. The strain harbours one of the largest prokaryotic genomes (13.1 Mbp). However, it codes only for three type I terpene synthases (TSs; sce1440, sce6369, sce8552) and one type II TS (sce4636), responsible for the production of at least 17 sesquiterpenes. We report here the gene expression of TSs and biosynthesis of the TS products in E. coli. Comparison with the So ce56 volatiles allows the assignment of the terpenes to their synthesizing genes. Both, the geosmin synthase sce1440 and the previously examined (+)-eremophilene synthase sce8552 are highly specific. In contrast, Sce6369, the first characterized 10-epi-cubebol synthase, is responsible for the formation of most of the So ce56 sesquiterpenes, mainly cadalanes and cubebanes. In contrast, Sce4636 does not convert FPP. Having characterized the So ce56 TSs, we screened all the 27 sequenced myxobacterial species from the NCBI and JGI-IMG databases for parent genes to predict the sesquiterpenes produced by them.