Young investigators in natural products chemistry, biosynthesis, and enzymology

• Jeffrey D. Rudolf,
• Lena Barra and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 2720–2721, doi:10.3762/bjoc.20.229

• clusters, and enzymes, development of chemical probes, biocatalysis and chemoenzymatic total synthesis, enzymatic mechanisms, and computational investigations of chemical structures and reactions. All of the major classes of natural products are represented here: nonribosomal peptides, ribosomally

• -synthesized and posttranslationally modified peptides, polyketides, alkaloids, aromatics, and terpenoids. This generation of young investigators will continue to shape the field of natural products for years to come. We pass on our greatest thanks to all the contributors to this special thematic issue. We

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• species. These glands can contain various lipids and peptides, but very often also complex mixtures of carboxylic acids. We report here the occurrence of novel methyl-branched unsaturated acids found in the secretions of six captive individuals living in a zoo. The structures of these compounds, 4.6

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• was achieved by Firipis et al. where they used SAXS to quantify hydrogels formed from self-assembling bioactive peptides Fmoc-DIKVAV and Fmoc-FRGDF (D = aspartic acid, I = isoleucine, K = lysine, V = valine, A = alanine, F = phenylalanine, R = arginine, G = glycine) [88]. The physical characteristics

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• provide unprecedented depth of proteome coverage and the possibility to detect desired modified peptides with high sensitivity. The chemical ‘linker’ connecting an active compound–protein conjugate with a detection tag is the critical component of all chemical proteomic workflows. In this review, we

• speed of acquisition of mass spectra leads to ever better coverage of proteomes submitted for analysis, the throughput has not yet reached the point in which all peptides and their modified forms can be identified and characterized in a single experiment. Therefore, an enrichment of the probe-modified

• peptides or enhancement of the signal-to-noise ratio is necessary for successful analysis (Figure 1). The future challenge to complete the chemical proteomic analysis will include the absolute quantification of those identified NP–peptide conjugates to estimate protein occupancy (Figure 1). Although mass

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• . FlexAID [123]: It is a molecular docking software capable of setting small molecules and peptides as ligands, and proteins and nucleic acids serve as docking targets. Notably, FlexAID shows support for full ligand flexibility and the flexibility of side chains in the target. It achieves this by employing

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• Matteo Gasparetto Balazs Fodi Gellert Sipos X-Chem Zrt., Záhony u. 7, DA Building, Graphisoft Park, Budapest, 1031, Hungary 10.3762/bjoc.20.168 Abstract Amino acids are vital motifs in the domain of biochemistry, serving as the foundational unit for peptides and proteins, while also holding a

• bifunctional building blocks (BBs) can quickly increase the diversity of these molecular libraries [6]. Hence, DEL practitioners constantly seek access to novel building blocks [7]. Amino acids (AAs) are vital motifs in the domain of biochemistry, serving as the foundational unit for peptides and proteins

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• substantial threat to global public health, demanding urgent attention and action. This study focuses on lanthipeptides, ribosomally encoded peptides that display significant structural diversity and hold promising potential as antibiotics. Genome mining was employed to locate biosynthetic gene clusters (BGCs

• , including one super-cluster containing two co-localized operons from Clostridium cellulovorans 743B, that encode for two new peptides named clostrisin and cellulosin. Each operon was heterologously expressed in Escherichia coli. Molecular weights associated with the expected post-translational modifications

• of the purified lanthipeptide were confirmed by MS–MS/MS analysis for cellulosin, while clostrisin was not post-translationally modified. Both peptides demonstrated antimicrobial activity against multidrug-resistant bacteria, such as a clinical strain of Staphylococcus epidermidis MIQ43 and

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

• engineered P450 enzymes catalyzed the site- and stereoselective oxidative modifications enabling further chemical transformations. Since the scaffolds of terpenes and ribosomally synthesized and post-translationally modified peptides (RiPPs) are first biosynthesized and then modified, the strategy of late

• , efficiency, and robustness of these biocatalysts are expected to enhance their usefulness and generality as synthetic tools. Apart from oxygenated terpenes and RiPPs, chemo-enzymatic approaches for polyketides and non-ribosomal peptides (NRPs) are considered more suitable for the second and third strategies

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

• allowing methylation at various positions. The different possible acceptor regions in ribosomally synthesised peptides are described in this article. Furthermore, we will discuss the potential application of these methyltransferases as powerful biocatalytic tools in the synthesis of modified peptides and

• -translational modifications; ribosomal peptides; SAM-dependent enzymes; Introduction In the complex landscape of natural product biosynthesis, ribosomally synthesised and post-translationally modified peptides (RiPPs) stand out as a fascinating class of compounds with both structural diversity and unique

• ; this reaction is catalysed by S-adenosylmethionine (SAM or AdoMet)-dependent methyltransferases (MTs). These enzymes are known for their excellent chemo-, regio-, and stereoselectivity [3][4][5][6]. Their ability to introduce methyl groups at specific positions within ribosomal peptides equips the

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

• classes of natural products isolated from Microbulbifer to date include alkaloids [15], fatty acid and polyketides [16][17], and non-ribosomally synthesized peptides [3][4][7]. These findings validate the potential for secondary metabolite discovery from Microbulbifer genus. This review will cover the

• 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

Regio- and stereochemical stability induced by anomeric and gauche effects in difluorinated pyrrolidines

• Ana Flávia Candida Silva,
• Francisco A. Martins and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2024, 20, 1572–1579, doi:10.3762/bjoc.20.140

• of the pyrrolidine ring in proline motifs has been found to induce significant conformational changes that impact the structure and biological roles of modified peptides and proteins. Vicinal difluorination of fluoroproline, for example, in (3S,4R)-3,4-difluoroproline, serves to mitigate the inherent

• pervade biochemistry in peptides and proteins. The chemical and biological properties of substituted pyrrolidine derivatives, along with many other compounds, hinge on the relative stereochemistry. It is well established that the presence of fluorine in an organic molecule can significantly influence the

Mining raw plant transcriptomic data for new cyclopeptide alkaloids

• Draco Kriger,
• Michael A. Pasquale,
• Brigitte G. Ampolini and
• Jonathan R. Chekan

Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138

• transcriptomic data sets, we uncover the potential distribution of split burpitide precursor peptides in Streptophyta. Metabolomic analysis of target plants confirms our bioinformatic predictions of new cyclopeptide alkaloids from both known and new sources. Keywords: burpitides; natural products; plants; RiPPs

• ; transcriptome mining; Introduction Plants are prolific producers of cyclic peptide natural products, making 1000s of different molecules [1]. While the orbitide [2] and cyclotide [3] classes of peptides are well known, it has been recently discovered that a new class of molecules called burpitides are also

• prevalent in plants [4]. Like all known plant peptides, burpitides fall under the ribosomally synthesized and post-translationally modified peptides (RiPPs) superclass of natural products (Figure 1). The typical pathway for a RiPP starts with a precursor peptide made by the ribosome that undergoes post

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• photosensitive arylketone catalyst in the fluorination of phenylalanine residues in peptides (Figure 27) [72]. This work demonstrated high yields and selectivity for peptides bearing phenylalanine residues, including tripeptides, such as 16. In 2015, Britton and co-workers reported a photochemical HAT-guided

• fluorination in continuous flow. Photochemical phenylalanine fluorination in peptides. Decatungstate-photocatalyzed versus AIBN-initiated selective benzylic fluorination. Benzylic fluorination using organic dye Acr+-Mes and Selectfluor. Palladium-catalysed benzylic C(sp3)–H fluorination with nucleophilic

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• biocatalysts, capable of catalyzing a wide range of reactions and processing a variety of substrates [35][36]. They effectively recognize different structural types, including aromatic compounds, polyketides, terpenes, peptides, and carbohydrates [37][38][39][40]. To investigate the substrate spectrum of CavA

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• of hydrophilic oligopeptide anchors (oligo-Lys, oligo-Glu, and oligo-Arg) were synthesized. A previously reported Prato reaction adduct of a biscarboxylic acid-substituted C60 derivative was subjected to a solid phase synthesis for amide formation with N-terminal amines of peptides on resin to

• C60–peptide conjugates in this study. In addition to the water solubility introduced by the peptides, these conjugates have a superior biocompatibility compared to those with synthetic polymers, such as PEG and PVP. We utilized the previously reported biscarboxylic acid derivative 3, which was

• suitable for the coupling to peptides on resin, prepared by solid-phase peptide synthesis (SPPS) [35]. The detailed conditions for the amide-forming reaction were optimized using biscarboxylic acid-substituted C60 derivative 3 and a similar peptide with a primary amine derived from γ-aminobutyric acid

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

• .20.66 Abstract Chemoenzymatic strategies that combine synthetic and enzymatic transformations offer efficient approaches to yield target molecules, which have been increasingly employed in the synthesis of bioactive natural products. In the biosynthesis of macrocyclic nonribosomal peptides, polyketides

• for these natural products that aim to address the common issues in classical synthetic approaches and increase synthetic efficiencies, which have the potential to facilitate further pharmaceutical research. Keywords: biosynthesis; chemoenzymatic synthesis; macrocyclic peptides; macrocyclic

• polyketides; thioesterase; Introduction Nonribosomal peptides, polyketides, and their hybrids exhibit significant diversity and a broad spectrum of bioactivities [1][2][3]. Particularly, macrocycles from these three categories of natural products are vital resources for developing pharmaceuticals and drug

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

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

• heptapeptides isolated predominantly from Aspergillus sp. [1][2][3][4][5][6][7][8]. Distinctive features of these cyclic peptides include the non-proteinogenic amino acid γ-aminobutyric acid (GABA) and the incorporation of up to five ᴅ-amino acids (Figure 1) [1][2][3][4][5][6][7][8]. The amino acids at

• 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

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• ramoplanin [2]. It is also the target for a host of other antimicrobials (mostly non-ribosomal peptides), including the tridecaptins [3], nisin [4], teixobactin [5], clovibactin [6], malacidin [7], and cilagicin [8]. Despite significant progress in the chemical synthesis of lipid II and its analogues, the

• study the mechanism of action of antimicrobial peptides that kill bacteria through binding to these polyprenyls [21][28][29][30][31][32][33][34]. Lipid II has been of particular interest, and during our synthesis of multiple different lipid II analogues, we have developed several optimizations, which we

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• ., vitamin B12, chlorophyll, metalloproteins, cyclic peptides, etc). PAMs themselves and their metal complexes exhibit various useful properties [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], particularly, they possess a wide range of biological activities and are used as contrast

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• acid organocatalysts were evaluated for sulfenylation on C3, or C2 position of N-heterocycles 115, including indoles, peptides, pyrrole, and 1-methyl-1H-pyrrolo[2,3-b]pyridine. The authors hypothesized a mechanism for the activation of N-sulfanylsuccinimides 1 or 14 by conjugate Lewis base Brønsted

• , peptides, drugs and saccharides reacted smoothly with N-alkynylthiophthalimides in the presence of TFA as a catalyst. Also, aliphatic and aromatic thiols reacted with N-alkynylthiophthalimide and sulfoxide 149 to obtain acyl disulfides 151 through alkynylthiolation and hydrative oxyarylation in the

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• solubility in water. Among exceptional properties belongs to easy post-transformation of acylimidazoles to common carbonyl analogs. These tunable properties allow the use of acylimidazoles in chemical biology research, which includes chemical synthesis of proteins/peptides, structure analysis, and functional

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• activity have revealed the presence of antimicrobial peptides [5], defensive alkaloids [6], and defensive long chain alcohol acetates [7]. Historically, in China, numerous records documented the utilization of animals like arthropods for medicinal purposes. Millipedes hereby represent a traditional Chinese

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• , sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural