Post-translational modifications involved in the biosynthesis of thiopeptide antibiotics

Mutasynthesis generates nine new pyrroindomycins

Pyrroindomycins (PYRs) represent the only spirotetramate natural products discovered in nature, and possess potent activities against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Their unique structure and impressive biological activities make them attractive targets for synthesis and biosynthesis; however, the discovery and generation of new PYRs remains challenging. To date, only the initial components A and B have been reported. Herein, we report a mutasynthesis approach for the generation of nine new PYRs with varying acyl modifications on their deoxy-trisaccharide moieties. This was achieved by blocking the formation of the acyl group 1,8-dihydropyrrolo[2,3-b]indole (DHPI) via gene pyrK1 inactivation and supplying chemical acyl precursors. The gene pyrK1 encodes a DUF1864 family protein that probably catalyzes the oxidative transformation of L-tryptophan to DHPI, and its deletion results in the abolishment of DHPI-containing PYRs and the accumulation of three new PYRs either without acyl modification or with DHPI replaced by benzoic acid and pyrrole-2-carboxylic acid. Capitalizing on the capacity of the ΔpyrK1 mutant to produce new PYRs, we have successfully developed a mutasynthesis strategy for the generation of six novel PYR analogs with various aromatic acid modifications on their deoxy-trisaccharide moieties, showcasing the potential for generating structurally diverse PYRs. Overall, this research contributes significantly to understanding the biosynthesis of PYRs and offers valuable perspectives on their structural diversity.

Heterologous Production of Antimicrobial Peptides: Notes to Consider

Heavy and irresponsible use of antibiotics in the last century has put selection pressure on the microbes to evolve even faster and develop more resilient strains. In the confrontation with such sometimes called "superbugs", the search for new sources of biochemical antibiotics seems to have reached the limit. In the last two decades, bioactive antimicrobial peptides (AMPs), which are polypeptide chains with less than 100 amino acids, have attracted the attention of many in the control of microbial pathogens, more than the other types of antibiotics. AMPs are groups of components involved in the immune response of many living organisms, and have come to light as new frontiers in fighting with microbes. AMPs are generally produced in minute amounts within organisms; therefore, to address the market, they have to be either produced on a large scale through recombinant DNA technology or to be synthesized via chemical methods. Here, heterologous expression of AMPs within bacterial, fungal, yeast, plants, and insect cells, and points that need to be considered towards their industrialization will be reviewed.

The role of proteinaceous toxins secreted by Staphylococcus aureus in interbacterial competition

Staphylococcus aureus is highly adapted to colonization of the mammalian host. In humans the primary site of colonization is the epithelium of the nasal cavity. A major barrier to colonization is the resident microbiota, which have mechanisms to exclude S. aureus. As such, S. aureus has evolved mechanisms to compete with other bacteria, one of which is through secretion of proteinaceous toxins. S. aureus strains collectively produce a number of well-characterized Class I, II, and IV bacteriocins as well as several bacteriocin-like substances, about which less is known. These bacteriocins have potent antibacterial activity against several Gram-positive organisms, with some also active against Gram-negative species. S. aureus bacteriocins characterized to date are sporadically produced, and often encoded on plasmids. More recently the type VII secretion system (T7SS) of S. aureus has also been shown to play a role in interbacterial competition. The T7SS is encoded by all S. aureus isolates and so may represent a more widespread mechanism of competition used by this species. T7SS antagonism is mediated by the secretion of large protein toxins, three of which have been characterized to date: a nuclease toxin, EsaD; a membrane depolarizing toxin, TspA; and a phospholipase toxin, TslA. Further study is required to decipher the role that these different types of secreted toxins play in interbacterial competition and colonization of the host.

Proteases Involved in Leader Peptide Removal during RiPP Biosynthesis

Ribosomally synthesized and post-translationally modified peptides (RiPPs) have received much attention in recent years because of their promising bioactivities and the portability of their biosynthetic pathways. Heterologous expression studies of RiPP biosynthetic enzymes identified by genome mining often leave a leader peptide on the final product to prevent toxicity to the host and to allow the attachment of a genetically encoded affinity purification tag. Removal of the leader peptide to produce the mature natural product is then carried out in vitro with either a commercial protease or a protease that fulfills this task in the producing organism. This review covers the advances in characterizing these latter cognate proteases from bacterial RiPPs and their utility as sequence-dependent proteases. The strategies employed for leader peptide removal have been shown to be remarkably diverse. They include one-step removal by a single protease, two-step removal by two dedicated proteases, and endoproteinase activity followed by aminopeptidase activity by the same protease. Similarly, the localization of the proteolytic step varies from cytoplasmic cleavage to leader peptide removal during secretion to extracellular leader peptide removal. Finally, substrate recognition ranges from highly sequence specific with respect to the leader and/or modified core peptide to nonsequence specific mechanisms.

Discovery and biosynthesis of tricyclic copper-binding ribosomal peptides containing histidine-to-butyrine crosslinks

Cyclic peptide natural products represent an important class of bioactive compounds and clinical drugs. Enzymatic side-chain macrocyclization of ribosomal peptides is a major strategy developed by nature to generate these chemotypes, as exemplified by the superfamily of ribosomally synthesized and post-translational modified peptides. Despite the diverse types of side-chain crosslinks in this superfamily, the participation of histidine residues is rare. Herein, we report the discovery and biosynthesis of bacteria-derived tricyclic lanthipeptide noursin, which is constrained by a tri amino acid labionin crosslink and an unprecedented histidine-to-butyrine crosslink, named histidinobutyrine. Noursin displays copper-binding ability that requires the histidinobutyrine crosslink and represents the first copper-binding lanthipeptide. A subgroup of lanthipeptide synthetases, named LanKC_Hbt, were identified to catalyze the formation of both the labionin and the histidinobutyrine crosslinks in precursor peptides and produce noursin-like compounds. The discovery of the histidinobutyrine-containing lanthipeptides expands the scope of post-translational modifications, structural diversity and bioactivity of ribosomally synthesized and post-translational modified peptides.

Biosynthesis of Antifungal Solanimycin May Involve an Iterative Nonribosomal Peptide Synthetase Module

Dickeya solani, a plant-pathogenic bacterium, produces solanimycin, a potent hybrid polyketide/nonribosomal peptide (PKS/NRPS) anti-fungal compound. The biosynthetic gene cluster responsible for synthesis of this compound has been identified. Because of instability, the complete structure of the compound has not yet been elucidated, but LC-MS2 identified that the cluster produces two main compounds, solanimycin A and B, differing by a single hydroxyl group. The fragmentation pattern revealed that the central part of solanimycin A is a hexapeptide, Gly-Dha-Dha-Dha-Dha-Dha (where Dha is dehydroalanine). This is supported by isotopic labeling studies using labeled serine and glycine. The N-terminal group is a polyketide-derived C16 acyl group containing a conjugated hexaene, a hydroxyl, and an amino group. The additional hydroxyl group in solanimycin B is on the α-carbon of the glycine residue. The incorporation of five sequential Dha residues is unprecedented because there is only one NRPS module in the cluster that is predicted to activate and attach serine (which is subsequently dehydrated to Dha), meaning that this NRPS module must act iteratively. While a few other iterative NRPS modules are known, they all involve iteration of two or three modules. We believe that the repetitive use of a single module makes the solanimycin biosynthetic pathway unique among NRPSs so far reported.

Comprehensive Approaches for the Search and Characterization of Staphylococcins

Novel and sustainable approaches are required to curb the increasing threat of antimicrobial resistance (AMR). Within the last decades, antimicrobial peptides, especially bacteriocins, have received increased attention and are being explored as suitable alternatives to antibiotics. Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria as a self-preservation method against competitors. Bacteriocins produced by Staphylococcus, also referred to as staphylococcins, have steadily shown great antimicrobial potential and are currently being considered promising candidates to mitigate the AMR menace. Moreover, several bacteriocin-producing Staphylococcus isolates of different species, especially coagulase-negative staphylococci (CoNS), have been described and are being targeted as a good alternative. This revision aims to help researchers in the search and characterization of staphylococcins, so we provide an up-to-date list of bacteriocin produced by Staphylococcus. Moreover, a universal nucleotide and amino acid-based phylogeny system of the well-characterized staphylococcins is proposed that could be of interest in the classification and search for these promising antimicrobials. Finally, we discuss the state of art of the staphylococcin applications and an overview of the emerging concerns.

Mutasynthesis Generates Antibacterial Benzothiophenic-Containing Nosiheptide Analogues

Nosiheptide is a bicyclic thiopeptide featuring an indole-containing side ring, which is biologically important in maintaining its potent antibacterial activity. By using mutational biosynthesis, the pharmaceutically significant benzothiophene was introduced into the nosiheptide biosynthetic pathway, resulting in the generation of three bioactive nosiheptide analogues with characteristic benzothiophene-containing side rings. Insights were provided into the transformation relationship of these analogues, which effectively improves the yield of S-NOS-1 with favorable activity against Gram-positive pathogens.

Host-dependent heterologous expression of berninamycin gene cluster leads to linear thiopeptide antibiotics

Berninamycins are a class of thiopeptide antibiotics with potent activity against Gram-positive bacteria. Heterologous expression of the berninamycin (ber) biosynthetic gene cluster from marine-derived Streptomyces sp. SCSIO 11878 in different terrestrial model Streptomyces hosts led to the production of berninamycins A (1) and B (2) in Streptomyces lividans SBT18 and Streptomyces coelicolor M1154, while two new linearized berninamycins J (3) and K (4) were obtained in Streptomyces albus J1074. Their structures were elucidated by detailed interpretation of NMR data and Marfey's method. Bioactivity assays showed that the linear thiopeptides 3 and 4 were less potent than 1 and 2 in antibacterial activity. This work indicates that undefined host-dependent enzymes might be responsible for generating the linear thiopeptides 3 and 4 in S. albus J1074.

Dissection of the Enzymatic Process for Forming a Central Imidazopiperidine Heterocycle in the Biosynthesis of a Series c Thiopeptide Antibiotic

Thiopeptide antibiotics are a family of ribosomally synthesized and posttranslationally modified peptide natural products of significant interest in anti-infective agent development. These antibiotics are classified into five subfamilies according to differences in the central 6-membered heterocycle of the thiopeptide framework. The mechanism through which imidazopiperidine, the most heavily functionalized central domain characteristic of a series c thiopeptide, is formed remains unclear. Based on mining and characterization of the genes specifically involved in the biosynthesis of Sch40832, we here report an enzymatic process for transforming a series b thiopeptide into a series c product through a series a intermediate. This process starts with F₄₂₀-dependent hydrogenation of the central dehydropiperidine unit to a saturated piperidine unit. With the activity of a cytochrome P450 monooxygenase, the piperidine-thiazole motif of the intermediate undergoes an unusual oxygenation-mediated rearrangement to provide an imidazopiperidine heterocycle subjected to further S-methylation and aldehyde reduction. This study represents the first biochemical reconstitution of the pathway forming a stable series c thiopeptide.

Characterization of Enterococcus faecium E86 bacteriocins and their inhibition properties against Listeria monocytogenes and vancomycin-resistant Enterococcus

In the present scenario of a major demand for new compounds with antimicrobial activity, bacteriocin and bacteriocin-like inhibitory substances (BLIS) are promising tools against deteriorating and pathogenic microorganisms, thus having potential applications in both the food industry and infectious disease control. In the present report, we describe the genetic and phenotypic characteristics of BLIS produced by Enterococcus faecium E86, a strain previously isolated and sequenced by our group, focusing on the structural genes of two bacteriocins identified: enterocin TW21 and enterocin P. Transcription of all four genes associated with the biosynthesis and immunity of enterocin P and enterocin TW21 were confirmed by RT-PCR. However, Sanger sequencing confirmed a truncation of the structural gene of enterocin TW21 due to one base pair deletion (A/T). Thus, although E. faecium E86 was shown to carry two bacteriocinogenic gene clusters, only one cluster encodes a functional bacteriocin, enterocin P. Enterocin P was able to inhibit different strains of Listeria monocytogenes and vancomycin-resistant enterococci (both Enterococcus faecalis and Enterococcus faecium), showing intense bacteriolytic activity, in most cases.

Posttranslational chemical installation of azoles into translated peptides

Azoles are five-membered heterocycles often found in the backbones of peptidic natural products and synthetic peptidomimetics. Here, we report a method of ribosomal synthesis of azole-containing peptides involving specific ribosomal incorporation of a bromovinylglycine derivative into the nascent peptide chain and its chemoselective conversion to a unique azole structure. The chemoselective conversion was achieved by posttranslational dehydrobromination of the bromovinyl group and isomerization in aqueous media under fairly mild conditions. This method enables us to install exotic azole groups, oxazole and thiazole, at designated positions in the peptide chain with both linear and macrocyclic scaffolds and thereby expand the repertoire of building blocks in the mRNA-templated synthesis of designer peptides.

Azoles are five-membered heterocycles found in peptidic natural products and synthetic peptiodomimetics. Here the authors demonstrate a posttranslational chemical modification method for in vitro ribosomal synthesis of peptides with exotic azole groups at specific positions.

Staphylococcins: an update on antimicrobial peptides produced by staphylococci and their diverse potential applications

Staphylococcins are antimicrobial peptides or proteins produced by staphylococci. They can be separated into different classes, depending on their amino acid composition, structural complexity, and steps involved in their production. In this review, an overview of the current knowledge on staphylococcins will be presented with emphasis on the information collected in the last decade, including a brief description of new peptides. Most staphylococcins characterized to date are either lantibiotics or linear class II bacteriocins. Recently, gene clusters coding for production of circular bacteriocins, sactipeptides, and thiopeptides have been mined from the genome of staphylococcal isolates. In contrast to class II bacteriocins, lantibiotics, sactipeptides, and thiopeptides undergo post-translational modifications that can be quite extensive, depending on the peptide. Few staphylococcins inhibit only some staphylococcal species, but most of them have proven to target pathogens belonging to different genera and involved in a variety of infectious diseases of clinical or agronomic importance. Therefore, these peptides exhibit potential application as anti-infective drugs in different areas. This review will also cover this diverse and remarkable potential. To be commercialized, however, staphylococcin production should be cost-effective and result in high bacteriocin yields, which are not generally achieved from the culture supernatant of their native producers. Such low yields make their production quite costly and not suitable at large industrial scale. Efforts already made to overcome this limitation, minimizing costs and time of production of some staphylococcins and employing either chemical synthesis or in vivo biosynthesis, will be addressed in this review as well. KEY POINTS: • Staphylococci produce a variety of antimicrobial peptides known as staphylococcins. • Most staphylococcins are post-translationally modified peptides. • Staphylococcins exhibit potential biotechnological applications. Graphical abstract.

Translation-Targeting RiPPs and Where to Find Them

Prokaryotic translation is among the major targets of diverse natural products with antibacterial activity including several classes of clinically relevant antibiotics. In this review, we summarize the information about the structure, biosynthesis, and modes of action of translation inhibiting ribosomally synthesized and post-translationally modified peptides (RiPPs). Azol(in)e-containing RiPPs are known to target translation, and several new compounds inhibiting the ribosome have been characterized recently. We performed a systematic search for biosynthetic gene clusters (BGCs) of azol(in)e-containing RiPPs. This search uncovered several groups of clusters that likely direct the synthesis of novel compounds, some of which may be targeting the ribosome.

Unrivalled diversity: the many roles and reactions of bacterial cytochromes P450 in secondary metabolism

Covering: 2000 up to 2018 The cytochromes P450 (P450s) are a superfamily of heme-containing monooxygenases that perform diverse catalytic roles in many species, including bacteria. The P450 superfamily is widely known for the hydroxylation of unactivated C-H bonds, but the diversity of reactions that P450s can perform vastly exceeds this undoubtedly impressive chemical transformation. Within bacteria, P450s play important roles in many biosynthetic and biodegradative processes that span a wide range of secondary metabolite pathways and present diverse chemical transformations. In this review, we aim to provide an overview of the range of chemical transformations that P450 enzymes can catalyse within bacterial secondary metabolism, with the intention to provide an important resource to aid in understanding of the potential roles of P450 enzymes within newly identified bacterial biosynthetic pathways.

Dehydroamino acids: chemical multi-tools for late-stage diversification

α,β-Dehydroamino acids (dhAAs) are noncanonical amino acids that are found in a wide array of natural products and can be easily installed into peptides and proteins. dhAAs exhibit remarkable synthetic flexibility, readily undergoing a number of reactions, such as polar and single-electron additions, transition metal catalyzed cross-couplings, and cycloadditions. Because of the relatively mild conditions required for many of these reactions, dhAAs are increasingly being used as orthogonal chemical handles for late-stage modification of biomolecules. Still, only a fraction of the chemical reactivity of dhAAs has been exploited in such biorthogonal applications. Herein, we provide an overview of the broad spectrum of chemical reactivity of dhAAs, with special emphasis on recent efforts to adapt such transformations for biomolecules such as natural products, peptides, and proteins. We also discuss examples of enzymes from natural product biosynthetic pathways that have been found to catalyze many similar reactions; these enzymes provide mild, regio- and stereoselective, biocatalytic alternatives for future development. We anticipate that the continued investigation of the innate reactivity of dhAAs will furnish a diverse portfolio dhAA-based chemistries for use in chemical biology and drug discovery.

The expanding structural variety among bacteriocins from Gram-positive bacteria

Bacteria use various strategies to compete in an ecological niche, including the production of bacteriocins. Bacteriocins are ribosomally synthesized antibacterial peptides, and it has been postulated that the majority of Gram-positive bacteria produce one or more of these natural products. Bacteriocins can be used in food preservation and are also considered as potential alternatives to antibiotics. The majority of bacteriocins from Gram-positive bacteria had been traditionally divided into two major classes, namely lantibiotics, which are post-translationally modified bacteriocins, and unmodified bacteriocins. The last decade has seen an expanding number of ribosomally synthesized and post-translationally modified peptides (RiPPs) in Gram-positive bacteria that have antibacterial activity. These include linear azol(in)e-containing peptides, thiopeptides, bottromycins, glycocins, lasso peptides and lipolanthines. In addition, the three-dimensional (3D) structures of a number of modified and unmodified bacteriocins have been elucidated in recent years. This review gives an overview on the structural variety of bacteriocins from Gram-positive bacteria. It will focus on the chemical and 3D structures of these peptides, and their interactions with receptors and membranes, structure-function relationships and possible modes of action.

The role of protein–protein interactions in the biosynthesis of ribosomally synthesized and post-translationally modified peptides

This review covers the role of protein–protein complexes in the biosynthesis of selected ribosomally synthesized and post-translationally modified peptide (RiPP) classes.

Built to bind: biosynthetic strategies for the formation of small-molecule protease inhibitors

The discovery and characterization of natural product protease inhibitors has inspired the development of numerous pharmaceutical agents.

Bioinformatic Expansion and Discovery of Thiopeptide Antibiotics

Thiopeptides are members of the ribosomally synthesized and post-translationally modified peptide family of natural products. Most characterized thiopeptides display nanomolar potency toward Gram-positive bacteria by blocking protein translation with several being produced at the industrial scale for veterinary and livestock applications. Employing our custom bioinformatics program, RODEO, we expand the thiopeptide family of natural products by a factor of four. This effort revealed many new thiopeptide biosynthetic gene clusters with products predicted to be distinct from characterized thiopeptides and identified gene clusters for previously characterized molecules of unknown biosynthetic origin. To further validate our data set of predicted thiopeptide biosynthetic gene clusters, we isolated and characterized a structurally unique thiopeptide featuring a central piperidine and rare thioamide moiety. Termed saalfelduracin, this thiopeptide displayed potent antibiotic activity toward several drug-resistant Gram-positive pathogens. A combination of whole-genome sequencing, comparative genomics, and heterologous expression experiments confirmed that the thioamide moiety of saalfelduracin is installed post-translationally by the joint action of two proteins, TfuA and YcaO. These results reconcile the previously unknown origin of the thioamide in two long-known thiopeptides, thiopeptin and Sch 18640. Armed with these new insights into thiopeptide chemical-genomic space, we provide a roadmap for the discovery of additional members of this natural product family.

Using Peptide Mimics to Study the Biosynthesis of the Side-Ring System of Nosiheptide

Thiopeptide natural products have gained interest recently for their diverse pharmacological properties, including antibacterial, antifungal, anticancer, and antimalarial activities. Due to their inherent poor solubility and uptake, there is interest in developing new thiopeptides that mimic these unique structures, but which exhibit better pharmacokinetic properties. One strategy is to exploit the biosynthetic pathways using a chemoenzymatic approach to make analogs. However, a complete understanding of thiopeptide biosynthesis is not available, especially for those molecules that contain a large number of modifications to the thiopeptide core. This gap in knowledge and the lack of a facile method for generating a variety of thiopeptide intermediates makes studying particular enzymatic steps difficult. We developed a method to produce thiopeptide mimics based on established synthetic procedures to study the reaction catalyzed by NosN, the class C radical S-adenosylmethionine methylase involved in carbon transfer to C4 of 3-methylindolic acid and completion of the side-ring system in nosiheptide. Herein, we detail strategies for overproducing and isolating NosN, as well as procedures for synthesizing substrate mimics to study the formation of the side-ring system of nosiheptide.

Ribosomal Natural Products, Tailored To Fit

Ribosomally synthesized and Post-translationally modified Peptides (RiPPs) take advantage of the ribosomal translation machinery to generate linear peptides that are subsequently modified with heterocycles and/or macrocycles to impose three-dimensional structure and thwart degradation by proteases. Although RiPP precursors are limited to proteinogenic amino acids, post-translational modifications (PTMs) can alter the structure of individual amino acids and thereby improve the stability and biological activity of the molecule. These "tailoring modifications" often occur on amino acid side chains-for example, hydroxylation, methylation, halogenation, prenylation, and acylation-but can also take place within the backbone, as in epimerization, or can result in capping of the N- or C-terminus. At one extreme, these modifications can be essential to the activity of the RiPP, either as a compulsory step in reaching the final molecule or by imparting chemical functionality required for biological activity. At the other extreme, tailoring PTMs may have little effect on the activity in an in vitro setting-possibly because of test conditions that do not match the biological context in which the PTMs evolved. Establishing the molecular basis for the function of tailoring PTMs often requires a three-dimensional structure of the RiPP bound to its biological target. These structures have revealed roles for tailoring PTMs that include providing additional hydrogen bonds to targets, rigidifying the RiPP structure to reduce the entropic cost of binding, or altering the secondary structure of the peptide backbone. Bacterial RiPPs are particularly suited to structural characterization, as they are relatively easy to isolate from laboratory cultures or to produce in a heterologous host. The identification of new tailoring PTMs within bacteria is also facilitated by clustering of the genes encoding tailoring enzymes with those of the RiPP precursor and primary modification enzymes. In this Account, we describe the effects of tailoring PTMs on RiPP structure, their interactions with biological targets, and their influence on RiPP stability, with a focus on bacterial RiPP classes. We also discuss the enzymes that generate tailoring PTMs and highlight examples of and prospects for engineering of RiPPs.

Bio-inspired engineering of thiopeptide antibiotics advances the expansion of molecular diversity and utility

Thiopeptide antibiotics, which are a class of sulfur-rich and highly modified peptide natural products, exhibit a wide variety of important biological properties. These antibiotics are ribosomally synthesized and arise from post-translational modifications, exemplifying a process through which nature develops the structural complexity from Ser/Thr and Cys-rich precursor peptides. Following a brief review of the knowledge gained from nature in terms of the formation of a common thiopeptide scaffold and its specialization to individual members, we highlight the significance of bio-inspired engineering, which has greatly expanded the molecular diversity and utility of thiopeptide antibiotics regarding the search for clinically useful agents, investigation into new mechanisms of action and access to typically 'inaccessible' biosynthetic processes over the past two years.

wblE2 transcription factor in Streptomyces griseus S4-7 plays an important role in plant protection

Streptomyces griseus S4‐7 was originally isolated from the strawberry rhizosphere as a microbial agent responsible for Fusarium wilt suppressive soils. S. griseus S4‐7 shows specific and pronounced antifungal activity against Fusarium oxysporum f. sp. fragariae. In the Streptomyces genus, the whi transcription factors are regulators of sporulation, cell differentiation, septation, and secondary metabolites production. wblE2 function as a regulator has emerged as a new group in whi transcription factors. In this study, we reveal the involvement of the wblE2 transcription factor in the plant‐protection by S. griseus S4‐7. We generated ΔwblE, ΔwblE2, ΔwhiH, and ΔwhmD gene knock‐out mutants, which showed less antifungal activity both in vitro and in planta. Among the mutants, wblE2 mutant failed to protect the strawberry against the Fusarium wilt pathogen. Transcriptome analyses revealed major differences in the regulation of phenylalanine metabolism, polyketide and siderophore biosynthesis between the S4‐7 and the wblE2 mutant. The results contribute to our understanding of the role of streptomycetes wblE2 genes in a natural disease suppressing system.

Drug design based on pentaerythritol tetranitrate reductase: synthesis and antibacterial activity of Pogostone derivatives

We performed molecular docking studies of Pogostone with PETNR and analyzed structure–activity relationships, which guided the structure design and the subsequent facile organocatalytic synthesis of Pogostone derivatives.