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

• Saarbrücken, Germany 10.3762/bjoc.15.286 Abstract The argyrins are secondary metabolites from myxobacteria with antibiotic activity against Pseudomonas aeruginosa. Studying their structure–activity relationship is hampered by the complexity of the chemical total synthesis. Mutasynthesis is a promising

• sarcosine (Sar) and derivatives. Chemical synthesis of the native sequence ᴅ-Ala-Dha-Sar thioester required revision of the sequential peptide synthesis into a convergent strategy where the thioester with sarcosine was formed before coupling to the Dha-containing dipeptide. Keywords: antibiotic; argyrin

• resistances in clinically used bacterial targets, innovative antiinfective strategies comprising new antibiotic classes and virulence-attenuating compounds have been developed [3][4]. The argyrins 1–8 are a family of 8 naturally occurring cyclic peptides isolated by Sasse, Höfle and co-workers from the

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• determining the minimum inhibitory concentration against two antibiotic-susceptible reference strains of S. aureus, S. aureus ATCC 25923 and S. aureus ATCC 29213 (see Supporting Information File 1, assay 1) [41]. Two-fold serial dilutions were performed, allowing to test several concentrations within the

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• , antibiotic, neuroprotective and even insecticidal activities, which makes these compounds high-value commercial targets for the chemical and pharmaceutical industry [9][10]. Structural diversity of diterpenes is created by the terpene synthase (TPS) enzyme family, which use acyclic isoprenoid precursors to

• -dolabellatriene (12) possesses a mainly weak antibiotic activity against different types of Staphylococcus aureus strains (two epidemic MRSA strains, a macrolide-resistant variant and two multidrug-resistant efluxing strains) [72]. By contrast, 3,7,18-dolabellatriene (12, Scheme 3), only altered at C14 with a

• substances, in addition to being key flavor ingredients [78], play a major role in the defence against insects, pathogenic microbes and herbivores [79]. Furthermore, β-CBT 17 showed additional antibiotic activity against multidrug resistant S. aureus strains, [80], as well as neuroprotective activity [81

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• -stimulating, and anticancer activities [2]. Since the World Health Organization (WHO) declared antibiotic resistance a global threat and urged the search for new antibiotics, the interest in fungal metabolites increased recently. In order to find new structural types, novel source organisms have to be

• laboratory [4]. E. terrae produced a novel antibiotic called teixobactin with no detectable resistance, as it interacts with key functions of cell wall synthesis that do not undergo fast evolutionary changes [5]. Inspired by this approach we developed the Fungal one-step IsolatioN Device (FIND), in order to

• axenic. From experiment 1, 39 isolates were microscopically identified as belonging to genera common in soil, e.g., Fusarium, Penicillium or Trichoderma and thus were not further processed. The addition of antibiotics prevented bacterial contamination in all marine samples. However, a few antibiotic

Cyclopropanation–ring expansion of 3-chloroindoles with α-halodiazoacetates: novel synthesis of 4-quinolone-3-carboxylic acid and norfloxacin

• Sara Peeters,
• Linn Neerbye Berntsen,
• Pål Rongved and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2019, 15, 2156–2160, doi:10.3762/bjoc.15.212

• efficient way of synthesizing two synthetically versatile 4-quinolone-3-carboxylate building blocks by cyclopropanation-ring expansion of 3-chloroindoles with α-halodiazoacetates as the key step. This novel transformation was applied towards the synthesis of the antibiotic drug norfloxacin. Keywords

• compounds with biological activities ranging from antitumor, antiviral, antibiotic and antiparasitic to cannabinoid receptor modulating [22][23][24][25][26][27][28]. Despite the attractive features of the quinolone-3-carboxylate scaffold, there are only four reported routes towards this valuable structural

• ]. Norfloxacin (1) is considered to be the first broad band antibiotic and its structurally related cousin ciprofloxacin (2) is one of the most prescribed antibiotics even after 20 years of clinical use. We elected 1 as a synthetic target for our novel approach towards FQs (Scheme 4). Chlorination of

Genome mining in Trichoderma viride J1-030: discovery and identification of novel sesquiterpene synthase and its products

• Xiang Sun,
• You-Sheng Cai,
• Yujie Yuan,
• Guangkai Bian,
• Ziling Ye,
• Zixin Deng and
• Tiangang Liu

Beilstein J. Org. Chem. 2019, 15, 2052–2058, doi:10.3762/bjoc.15.202

• structurally diverse (poly)cyclic core skeletons [3][12]. A set of post-modification enzymes can transform core sesquiterpene skeletons into different kinds of sesquiterpenoids with potential anticancer, cytotoxic and antibiotic functions [13]. More than 121 skeleton structures derived from the sesquiterpene

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• Leticia Monjas Peter Fodran Johanna Kollback Carlo Cassani Thomas Olsson Maja Genheden D. G. Joakim Larsson Carl-Johan Wallentin Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96, Gothenburg, Sweden Centre for Antibiotic Resistance Research (CARe

• : abyssomicin C; antibiotic; antibiotic resistance; MRSA; truncated natural products; Introduction Antibiotic resistance is a major threat to global health, and numerous actions are presently taken in both academia and industry to combat this major societal challenge. There are many different approaches to

• the same time, and these compounds did not show any antibacterial activity (Figure 1). Consequently, the enone moiety of AbC was proposed to play an essential role in the antibiotic activity. Indeed, in a subsequent study it was shown that AbC has a unique mechanism of action amongst NPs: it is a

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

• ]. In this study, we analyzed the β-proteobacterium Massilia sp. NR 4-1, which had been isolated from a soil sample collected under a nutmeg tree [6]. Although, this strain had already been identified as producer of the antibiotic violacein [6], still not much is known about its secondary metabolism or

Phylogenomic analyses and distribution of terpene synthases among Streptomyces

• Lara Martín-Sánchez,
• Kumar Saurabh Singh,
• Mariana Avalos,
• Gilles P. van Wezel,
• Jeroen S. Dickschat and
• Paolina Garbeva

Beilstein J. Org. Chem. 2019, 15, 1181–1193, doi:10.3762/bjoc.15.115

• crystal structure of 2-MIB synthase. The function of this domain is unknown, but it is conserved in most 2-MIB synthases and not present in any other terpene synthase [20][28]. epi-Isozizaene (3) is a tricyclic sesquiterpene precursor of the antibiotic albaflavenone (17) (Scheme 3) [29]. Furthermore, both

• crystal structure was also the first reported for a bacterial terpene synthase [47]. Pentalenene synthase catalyses the cyclisation of FPP into pentalenene, which is the first step in the biosynthesis of the antibiotic pentalenolactone. This mechanism has been extensively studied and involves the initial

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• compounds. Molecules containing the isoindolinone moiety are of pharmaceutical interest as anxiolytic (pazinaclone [15], pagoclone [16], and JM1232 [17]), anticancer (lenalidomide) [18], anti-inflammatory (indoprofen) [19] and antibiotic agents (lactonamycin) [20] (Figure 4). In addition, some isoindolinone

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• with high affinity to lectins and with antibiotic activities [34], lectin recognition by n-alkyl thioglycoside liposomes remains unprecedented [33][34]. Moreover, the calculated distance between the two sugar moieties of compound 8 (up to 13 Å, Figure 6) and the presence of flexible arms make these

Diastereo- and enantioselective preparation of cyclopropanol derivatives

• Marwan Simaan and
• Ilan Marek

Beilstein J. Org. Chem. 2019, 15, 752–760, doi:10.3762/bjoc.15.71

• transformations [1]. The cyclopropane subunit is also present in many biologically important compounds such as pheromones, fatty acid metabolites, unusual amino acids and possess interesting herbicidal, insecticidal, antibiotic, antibacterial, antifungal, antiviral and antitumor activities [2]. For these reasons

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• -7 cells were cultured in RPMI medium supplemented with fetal bovine serum (10%), antibiotic–antimycotic (1.0%). MCF-10A cells were cultured in α-MEM supplemented with FBS (10%), and antibiotic–antimycotic (1.0%). All cells were cultured in an environment equilibrated with 5% CO2 at 37 °C. The cell

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• nature and have excellent biological activity, including strong antibiotic, antihelmetic, antifungal, antitumor, antiviral and anti-inflammatory, which make them interesting lead structures for new drugs [34]. That is why a great deal of attention has been paid to the synthesis of the lactone ring [35

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• biological activity. Indeed, the interest in 3-hydroxyglutamic acid started many years ago by the discovery of this amino acid in hydrolysates of an antibiotic peptide S-520 [24]. It has been proved recently that it was actually the isomer (2S,3R)-2 and it is a fragment of a cyclohexapeptide [25]. (2R,3S)-2

• was much lower (2.6:1 and 1:1, respectively). Acid hydrolysis of 64 gave (4S)-4-hydroxy-L-glutamic acid [(2S,4S)-3] as the hydrochloride, however, its enantiomeric purity was not checked. In connection with the total synthesis of thiopeptide antibiotic nosiheptide an orthogonally protected (4S)-4

• orthogonally protected (2S,4S)-4-hydroxyglutamic acid 85 as an intermediate in the total synthesis of antibiotic nosiheptide [83][84] employs the N-Boc derivative of natural (2S,4R)-4-hydroxyproline 82 as a starting material (Scheme 21) [84][85]. The inversion of configuration at C4 was carried out by

Synthesis and biological activity of methylated derivatives of the Pseudomonas metabolites HHQ, HQNO and PQS

• Sven Thierbach,
• Max Wienhold,
• Susanne Fetzner and
• Ulrich Hennecke

Beilstein J. Org. Chem. 2019, 15, 187–193, doi:10.3762/bjoc.15.18

• in the lung of cystic fibrosis patients, was inhibited in planktonic growth and cellular respiration by the 4-O-methylated derivatives of HQNO and HHQ, respectively. Keywords: antibiotic acitivity; methylation; Pseudomonas aeruginosa; quinolones; quorum sensing; Introduction 2-Alkyl-4(1H

• the desired product 12. Nevertheless, enough material could be obtained to enable biological investigations on this compound. Growth inhibition of S. aureus To get a better understanding of the influence of methylation on the antibiotic properties of AQ compounds, their effect on the growth of S

• . aureus Newman was investigated (Figure 1). To be able to compare the growth in the presence of the only weakly antibiotic HHQ derivatives, growth experiments were conducted at a concentration of 100 µM. Planktonic cultures of P. aeruginosa in LB medium were reported to contain up to 50 µM PQS and up to

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• disease is strongly influenced by localized poverty and the efficiency of regional health care systems, and nowadays is further complicated by the rapidly increasing prevalence of antibiotic-resistant Mtb strains [2]. To successfully combat this disease, it is important to improve our understanding of Mtb

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• 637371 Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 København N, Denmark 10.3762/bjoc.14.284 Abstract Antibiotic resistance threatens effective treatment of microbial infections globally. This situation has spurred the hunt for new antimicrobial

• effective than the clinically used antibiotic tobramycin in eradicating biofilms. Although cisplatin is highly toxic for intravenous applications, we showed that it has low toxicity when applied topically to wounds, as 25 mM (0.75 mg mL−1) did not have adverse effect on wound healing. This meant that higher

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• Roseobacter group (Rhodobacteraceae) are important members of many marine ecosystems. Similar to other Gram-negative bacteria many roseobacters produce N-acylhomoserine lactones (AHLs) for communication by quorum sensing systems. AHLs regulate different traits like cell differentiation or antibiotic

• knowledge on their biosynthesis, the underlying gene organization, as well as their function in many bacteria [11][12][13]. In the Roseobacter group, AHLs are involved, e.g., in antibiotic production [9] or cell differentiation [10]. Although many other bacterial signalling compounds must exist, only few of

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• vinyl ethers as key step of reaction sequences developed. Keywords: 3-amino glycals; diastereoselective additions to aldehydes; pluramycins; ring-closing metathesis; vinyl ethers; Introduction Several classes of medicinally useful molecules with antibiotic and anticancer activity contain in their

Protein–protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics

• Laura Carro

Beilstein J. Org. Chem. 2018, 14, 2881–2896, doi:10.3762/bjoc.14.267

• Laura Carro School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK 10.3762/bjoc.14.267 Abstract Antibiotics are potent pharmacological weapons against bacterial infections; however, the growing antibiotic resistance of microorganisms is compromising the efficacy

• of the currently available pharmacotherapies. Even though antimicrobial resistance is not a new problem, antibiotic development has failed to match the growth of resistant pathogens and hence, it is highly critical to discover new anti-infective drugs with novel mechanisms of action which will help

• medicine. Unfortunately, since their use is intrinsically linked to the appearance of resistance, threatening antibiotic-resistant bacteria levels are being observed, compromising the efficacy of nearly all available antibiotics to cure infectious diseases [2][3][4]. The rise in the percentage of

Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium

• Matthew J. Styles and
• Helen E. Blackwell

Beilstein J. Org. Chem. 2018, 14, 2651–2664, doi:10.3762/bjoc.14.243

• bacteriostatic chemotherapies to treat infection imposes evolutionary pressures that drive rapid resistance development and spread within and among bacterial populations [2][3]. Antibiotic resistant clinical isolates have been observed for almost every known antibiotic, and the pace of new antibiotic discovery

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• , Department of Infection, Immunity and Inflammation, University of Leicester, Maurice Shock Medical Sciences Building, University Road, Leicester, LE1 9HN, UK 10.3762/bjoc.14.242 Abstract Siderophore–antibiotic conjugates consist of an antibiotic covalently linked by a tether to a siderophore. Such

• antibacterial agents. Keywords: NDH-2; phenothiazine; siderophore; siderophore–antibiotic; siderophore conjugate; Introduction One of the biggest challenges facing the modern society is antibiotic resistance and the prospect of current antibiotics becoming near redundant against previously treatable

• infections [1]. To meet this challenge there is a desperate need for new antibiotics, antibiotic targets and strategies to enhance the efficacy of current antibiotics [2]. One novel strategy which is receiving significant interest is the manipulation of bacterial iron transport pathways to deliver

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• infections [2]. Especially in the case of Gram-negative bacteria, an urgent need for novel medicines has been identified while the pipeline of drug candidates is literally running dry and a desirable renaissance of the golden age of antibiotic drug research in ‘big pharma’ is currently not to be seen on the

• horizon [3][4]. Nevertheless, some innovative strategies to be explored for their clinical applicability in combating bacterial infections have been devised in the last decades mostly driven by academic research [5][6][7]. In contrast to addressing classical antibiotic drug targets involved in vital

• resist antibiotic treatment via several mechanisms. First and foremost, it possesses an intrinsic resistance to many antibiotics because of the low permeability of its cell wall and due to the action of a number of efflux pumps as well as β-lactamases. Efflux pumps in particular are nifty molecular