Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• (PKS–NRPS) [13]. Based on the structural relations between farinosones and tenellins differing only in the side chain length/the number of conjugated double bonds, farinosones were also postulated to be synthesized adopting a similar biosynthetic pathway. The biosynthesis of farinosones (Figure 4

• -ketoheptaketide that would in turn combine to a tyrosine moiety bound to NRPS to afford the first tetramic acid derivative. Then, oxygenation at C-2’ of the afforded first product followed by tautomerization would yield farinosone D (1), whereas oxidative ring expansion instead of tautomerization would produce

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• of saframycin A (1) is assembled from two molecules of ʟ-tyrosine derivative 5 and peptidyl aldehyde 6 by non-ribosomal peptide synthetases (NRPS, Scheme 1a) [15][16][17][18][19][20][21]. The pivotal NRPS module, SfmC, catalyzes iterative regio- and stereoselective Pictet–Spengler (PS)-type

• , excited at 375 nm): 0.07 (c = 10 μM). Emission image was captured under UV light (365 nm, c = 100 μM in CHCl3). Strategies for the construction of the pentacyclic core scaffold of saframycin A (1). (a) Biosynthetic machinery catalyzed by an NRPS module SfmC. (b) Total syntheses utilizing the Pictet

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• ) from microorganisms have been the focus of chemical structure metagenomics approaches thus far, it is in principle applicable to other natural product families as well, and the possibility of extending it beyond NRPs will be discussed at the end. Chemical structure is the universal language of nature

• product. Specifically, it is now possible to predict the order and identity of the BBs in NRPs based solely on the nucleic acid sequences of its BGC [40][41][42][43][44][45][46][47][48][49]. These algorithms not only obviated the need for culture and gene expression, dereplication can now be done in

• silico to avoid rediscovery. They are the cornerstone of chemical structure metagenomics; a few examples in this area of research are described below. NRP biosynthesis and structure prediction NRPs are biosynthesized by either type I or II nonribosomal peptide synthetase (NRPS) [50][51]. Type I NRPS is a

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• carboxylic acids followed by intramolecular condensation. As a chemo-enzymatic complementary strategy, thioesterase (TE) domains of NRPS and PKS gene clusters have been utilized as enzymes for macrolactone formation to produce a wide range of natural/non-natural macrocyclic compounds [58][59][60][61][62][63

• vitro enzymatic conversions (Scheme 9) [94]. The biosynthesis of 5 begins with the conversion of ʟ-tyrosine to tyrosine derivative 86 (Tyr*) by peroxygenase SfmD and the methyltransferases, SfmM2 and M3 [95][96]. Concurrently, two non-ribosomal peptide synthetase (NRPS) modules, SfmA and SfmB, catalyze

• the successive condensation of myristic acid, ʟ-alanine, and glycine to furnish thioester 87 on the peptidyl carrier protein (PCP) domain of SfmB [94][97]. The downstream NRPS module, SfmC, then catalyzes sequential reactions with 86 and 87 to assemble pentacyclic scaffold 93 in a single stroke [97

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• can also be employed to mimic non-ribosomal peptides [12][13], since it is substantially more challenging to engineer non-ribosomal peptide synthetase (NRPS) pathways. Non-ribosomal peptides are often produced by giant multi-modular enzyme complexes (type I NRPS) and they are most commonly involved in

• the specialised metabolism of bacteria and fungi. Each NRPS module is minimally composed of a condensation (C) domain, an adenylation (A) domain, and a peptidyl carrier protein (PCP or thiolation/T domain), and one module typically incorporates one amino acid into the final natural product. In

• peptide methylation. Biocatalysis provides an efficient and sustainable alternative to chemical synthesis strategies. Both NRPS and RiPP biosynthetic machineries can be used for cell-based or in vitro strategies [53]. Especially well suited as biocatalysts are MTs from RiPP pathways, as they demonstrate

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• NRPS-derived macrolactam ureidopeptide, bulbiferamide (27, Figure 10), was isolated and characterized from a coral-derived Microbulbifer sp. C10-1 by Igarashi and co-workers [7]. The ureido linkage did not allow for the peptide main chain in 27 to possess a terminal primary amine and none of the side

• publicly available which are typically 5 Mbp in size. Computational mining these genomes with antiSMASH reveals that these bacteria, though not endowed with the biosynthetic prowess of actinomycetes, do still possess BGCs encoding NRPS-derived peptides, polyketides, RiPPs, and siderophores [4][147]. A

• products isolated from Microbulbifer (the corresponding BGCs and NRPS assembly lines are identified as denoted in Figure 11) [3][4]. Thus, it is immediately apparent that the potential for novel compound discovery and for the heterologous production of cryptic natural products from this genus is high

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

• Changjun Xiang,
• Shunyu Yao,
• Ruoyu Wang and
• Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

• bioinformatics perspective, and will facilitate accurate stereochemical prediction and genome mining of complex polyketides. Experimental Sequence collection and screening All cis-AT PKS and PKS-NRPS amino acid sequences recorded in MIBiG, as well as the PKS sequences reported in literatures we have curated were

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• compound is made through a trans-AT polyketide synthase–non-ribosomal peptide synthase (PKS-NRPS) hybrid [9][10]. Instead of using the classical domain organisation KS-AT-ACP with AT domains integrated into the PKS, trans-AT PKSs utilize discrete ATs that are not an integral part of the PKS, but rather

• presence of two major compounds, bacillaene (1) and dihydrobacillaene (2) (Scheme 1), and allowed for a detailed biosynthetic model [14]. As is typical for trans-AT systems, the bacillaene PKS-NRPS contains several irregular features such as split modules and duplicate ACP domains. Because of the absence

• substrate specificity of such KS domains [20]. Especially the KS domains of a PKS module downstream of an NRPS module need to be able to process unconventional NRPS-derived intermediates [21]. Despite the above mentioned predictability of KS domain substrate specificities, functional testing of KS domains

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• and multifunctional enzymatic assembly, nonribosomal peptide synthases (NRPS), polyketide synthases (PKS), and hybrid NRPS/PKS systems, which are organized into sets of functional domains known as modules and function through a similar mechanism [9][10][11][12]. Each NRPS module is composed of three

• responsible for the structural diversity of natural products, both NRPS and PKS contain thioesterase (TE) domains in the final elongation module, which contribute to terminating biosynthesis [13][14]. Typically, TE domains cleave the thioester bond between the last PCP or ACP domain and the intermediate of

• -century [32][33][34][35]. Biosynthetically, the corresponding cluster consists of three NRPS, TycA-C, and at the C-terminus of TycC, the TE domain can catalyze a head-to-tail macrocyclization and deliver tyrocidines [30]. With a comprehensive understanding of its biosynthetic mechanism, Walsh and co

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• draft genome sequence of the H002 strain identified the variochelin biosynthetic gene cluster (var), which encodes PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetase) genes. Finally, the siderophores isolated in this study exhibited antibacterial activity against several bacteria

• , we also identified a var gene cluster containing NRPS and PKS genes: the domain organizations of NRPS and PKS, and the adjacently encoded modification enzymes, were comparable to those of the gene cluster reported by Nett et al. with 92–99% identity at the protein level [5] (Figure 3a and Figure S42

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• version of antiSMASH 7.0 [25] software for the analysis of the Penicillium shentong XL-F41 genome, we identified 46 BGCs. These include 13 NRPS-like fragments, 6 NRPS, 13 type I PKS, 2 PKS/NRPS hybrids, 1 NI-siderophore, 2 NRP-metallophore/NRPS hybrids, 1 fungal RiPP with POP or UstH peptidase types, 1

• fungal-RiPP-like/T1PKS, 1 betalactone, 1 PKS type I/NRPS/indole hybrid, 1 fungal-RiPP-like/T1PKS hybrid, 1 NRP-metallophore/NRPS hybrid, NRPS-like/terpene/phosphonate hybrids, 3 terpenes, and 1 indole-related cluster (Table 5). BGC 7.3, identified as an indole-type gene cluster, includes genes for

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• ; Introduction Nonribosomal peptides (NRPs) exhibit various biological activities and have been used as therapeutic agents, such as antibiotics, anticancer agents, and immunosuppressants [1]. Additionally, NRPs function as virulence factors, such as siderophores and genotoxins [2]. Therefore, inhibiting their

• biosynthesis by using small molecules can help to elucidate their natural functions and their potential as therapeutic targets. NRPs are synthesized by large, versatile, and multifunctional proteins called nonribosomal peptide synthetases (NRPSs), which are composed of multiple modules and subdivided domains

• ) domain, consequently resulting in the formation of the final products. Inhibitors that target each domain of NRPSs are valuable for elucidating the biosynthetic pathways associated with bioactive NRPs and for developing antibiotic molecules. Burkart et al. reported a systematic strategy for inhibiting

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• of the UngA NRPS were analyzed in an attempt to understand the lack of substrate specificity observed. Keywords: adenylation domain; condensation domain; fungal non-ribosomal peptide synthetase; heptapeptide; unguisin biosynthesis; Introduction Unguisins are a small family of fungal cyclic

• small peptides [3][4][9], however, unguisin A has been shown to bind a series of anions [10]. Recently the biosynthesis of unguisins A and B from Aspergillus violaceofuscus CBS 115571 was reported [5]. A seven module non-ribosomal peptide synthetase (NRPS; UngA) was heterologously expressed in

• discovered that linearized the cyclic unguisins to linear peptides during in vitro investigations, although the linear peptides were not detected from the fungal cultures. NRPS enzymes are large multifunctional enzymes that often synthesize very important bioactive molecules [11][12]. These enzymes consist

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• great structural variability such as polyketides, terpenoids, polyketide synthase–nonribosomal peptide synthetase (PKS–NRPS) alkaloids, and cytochalasins, which have been considered as taxonomic markers of the genus [7][8][9][10]. However, it is worthwhile to mention that the name Phomopsis should no

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• combination of all genome mining approaches will pave the way towards a more comprehensive understanding of the full biosynthetic repertoire encoded in microbial genome sequences. Keywords: genome mining; natural product biosynthesis; non-canonical pathways; PKS; NRPS; RiPP; Introduction In 2002, the genome

• -like pathways are canonical type I cis-acyltransferase polyketide synthases (PKSs) and type A non-ribosomal peptide synthetases (NRPSs) (Figure 2A) [25][26]. The substrate specificity of the specificity conferring domains in each module can be predicted from the sequences of adenylation (A) (for NRPS

• ])) [28]. In contrast, discrete multi-enzymatic assemblies utilize distinct, monofunctional enzymes. Examples are terpene (e.g., cyclooctatin (8) [29]), ribosomally synthesized and post-translationally modified peptide (RiPP), or NRPS-independent alkaloid pathways. In the case of terpene biosynthesis

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• -AT, [3][4]) polyketide synthase (PKS) and non-ribosomal peptide synthase (NRPS) [2] with a dehydrating bimodule [5][6] involved in the installation of the remaining Z-configured double bond within the polyketide backbone [7]. Furthermore, a cytochrome P450 monooxygenase was recently shown to be

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• metabolites for self-defense in different microorganisms, peptidic natural products are assembled either by ribosomal synthesis or by non-ribosomal peptide synthetases (NRPS) [2]. Macrocyclic peptides are pervasive throughout this class of natural products and often show improved stability against proteolytic

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

• Jana M. Boysen,
• Nauman Saeed and
• Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

• foundation to understand its role in invasive aspergillosis [113]. In A. fumigatus 13 genes form a 28 kb biosynthetic cluster of gliotoxin, of which gliZ (a zinc-finger transcription factor) and gliP (an NRPS) together with global regulator LaeA regulate its expression at the genomic level [112][114][115

Secondary metabolites of Bacillus subtilis impact the assembly of soil-derived semisynthetic bacterial communities

• Heiko T. Kiesewalter,
• Carlos N. Lozano-Andrade,
• Mikael L. Strube and
• Ákos T. Kovács

Beilstein J. Org. Chem. 2020, 16, 2983–2998, doi:10.3762/bjoc.16.248

• , Kgs. Lyngby, Denmark 10.3762/bjoc.16.248 Abstract Secondary metabolites provide Bacillus subtilis with increased competitiveness towards other microorganisms. In particular, nonribosomal peptides (NRPs) have an enormous antimicrobial potential by causing cell lysis, perforation of fungal membranes

• Lysinibacillus fusiformis M5 exposed to either spent media of the B. subtilis strains or pure surfactin indicated the sensitivity of this strain towards the biosurfactant surfactin. Our study provides a more in-depth insight into the influence of B. subtilis NRPs on semisynthetic bacterial communities and helps

• Bacillus spp. produce various SMs [33][34]. The most prominent and bioactive SMs are nonribosomal peptides (NRPs), of which isoforms belong to the families of surfactins, fengycins, or iturins [35][36] (Figure 1). They are biosynthesised by large enzyme complexes, nonribosomal peptide synthetases (NRPSs

Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• for bioactive compounds are required, such as the bacterial genera Xenorhabdus or Photorhabdus. In these strains, fabclavines are widely distributed SMs with a broad-spectrum bioactivity. Fabclavines are hybrid SMs derived from nonribosomal peptide synthetases (NRPS), polyunsaturated fatty acid (PUFA

• of fabclavines as major antibiotics in several entomopathogenic strains, our work lays the foundation for the rapid fabclavine identification and dereplication as the basis for future work of this widespread and bioactive SM class. Keywords: antibiotic; fabclavine; NRPS-PKS hybrid; secondary

• ]. Fabclavines are hexapeptide/polyketide hybrids derived from nonribosomal peptide synthetases (NRPS) and a polyketide synthase (PKS), which are connected to an unusual polyamine derived from polyunsaturated fatty acid (PUFA) synthases [20]. Beside full-length fabclavines, also shortened derivatives were

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• (Cmc5) by the groups of Höfle and Reichenbach in 2003 [12]. This PKS/NRPS-derived natural product shows only weak antibiotic effects in agar diffusion tests against Micrococcus luteus, Schizosaccharomyces pombe, Bacillus subtilis and Staphylococcus aureus [12]. The relative and absolute stereochemistry

Chemical synthesis of tripeptide thioesters for the biotechnological incorporation into the myxobacterial secondary metabolite argyrin via mutasynthesis

• David C. B. Siebert,
• Roman Sommer,
• Domen Pogorevc,
• Michael Hoffmann,
• Silke C. Wenzel,
• Rolf Müller and
• Alexander Titz

Beilstein J. Org. Chem. 2019, 15, 2922–2929, doi:10.3762/bjoc.15.286

• ; mutasynthesis; NRPS; peptide synthesis; Introduction Resistance to antibiotics is currently a major threat to public health. Especially Gram-negative bacterial pathogens are of concern, due to their widespread development of resistance mechanisms. To address this general antimicrobial resistance problem, new

• synthetase (NRPS), mutasynthons often carry thioesters to mimic the natural phosphopantetheinyl conjugate [20]. For the argyrins, the Müller group identified the corresponding biosynthetic gene cluster from Cystobacter sp. SBCb004 [21], studied the biosynthesis (Figure 2) and established a heterologous

• derivatives upon incorporation of synthetically provided tripeptide thioester intermediates, the so called mutasynthons. Mutasynthons are synthesized as SNAc thioesters which mimic the phosphopantetheine (PPant) moiety normally present on the PCP domain of the NRPS. It has been shown by several mutasynthesis

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

• Eric J. N. Helfrich,
• Geng-Min Lin,
• Christopher A. Voigt and
• Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

• thiotemplated assembly lines, such as type I polyketide synthases (PKS) and nonribosomal peptide synthetases (NRPS), are modular, with each module contributing a distinct fragment to the final product’s core structure – a short-chain carboxylic acid (PKS) or an amino acid (NRPS). The modularly defined template

• allow for quantitative control of product outcomes, while PKS and NRPS pathways feature qualitative control [40]. The gibberellins (e.g., gibberellin A4 (5), Figure 1) are an extreme example illustrating the promiscuity of terpene biosynthetic pathways with more than 130 different family members

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• second report on the small molecule from this underexplored taxon. According to the genome sequence database, biosynthetic genes for NRPS and siderophore are present in Microbulbifer species which will be pursued in our future investigation. Experimental General experimental procedures The UV spectrum

Genomics-inspired discovery of massiliachelin, an agrochelin epimer from Massilia sp. NR 4-1

• Jan Diettrich,
• Hirokazu Kage and
• Markus Nett

Beilstein J. Org. Chem. 2019, 15, 1298–1303, doi:10.3762/bjoc.15.128

• homologs in the mic cluster from R. solanacearum GMI1000 [13]. A closer inspection of the loci shows a strong conservation of two core biosynthesis genes, namely micC and micG. On the other hand, the nonribosomal peptide synthetase (NRPS) gene micH is missing in the Massilia locus. As evidenced by