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PubMed2026

Unlocking antifungal mechanisms of natural 3-(oxazole-5-yl) indole compound derived from Streptomyces syringium against plant gray mold caused by Botrytis cinerea.

BACKGROUND: Plant fungal diseases cause significant agricultural losses, and Streptomyces-derived antifungal compounds offer a promising biocontrol strategy. This study aimed to isolate and characterize bioactive metabolites from Streptomyces syringium LZ036 and evaluate their activity and mechanism of action against Botrytis cinerea. RESULTS: A strain LZ036 with broad-spectrum antifungal activity was identified as Streptomyces syringium. The 3-(oxazole-5-yl) indole compound NL3 isolated from this strain exhibited potent broad-spectrum antifungal activity, especially against Botrytis cinerea. Compound NL3 inhibited fungal growth and development by inducing severe oxidative damage and membrane disruption. And it could trigger jasmonic acid (JA)-dependent induced systemic resistance (ISR) in plants. Transcriptomic analysis of compound NL3-treated Botrytis cinerea revealed genome-wide transcriptional alterations, including disruption of energy metabolism and mitochondrial function. Key genes related to mitogen-activated protein kinase (MAPK) signaling pathway down-regulated significantly, among which the catalytic S_TKc domain of Bcste7 exhibited a predicted interaction with compound NL3 through hydrophobic interactions and hydrogen bonding. CONCLUSION: The Streptomyces syringium-derived compound NL3 shows high potential as a green fungicide, acting through multiple mechanisms. These findings advance the development of Streptomyces-based antifungal agents. © 2026 Society of Chemical Industry.

3‐(oxazole‐5‐yl) indole compo↗
PubMed2026

A Pseudokinase Catalyzes Nitrile Formation in the Biosynthesis of a Potent Marine Toxin.

Several pseudokinases, previously regarded as dead enzymes due to the lack of catalytic residues, catalyze nucleotidylation. While they often utilize macromolecular substrates such as proteins and RNAs in primary metabolism, those acting on non-macromolecules in specialized metabolisms are limited. Calyculin A, a cytotoxic natural product produced by an uncultured sponge symbiont, possesses a unique nitrile group at the end of its tetraene tail. Even though its biosynthetic gene cluster (BGC) has been identified, the enzyme responsible for nitrile formation remains unknown. Herein, through a comparative analysis of the BGCs for calyculin derivatives in symbiotic bacteria from distinct sources, we identified a novel nitrile-forming enzyme, CalN. While CalN lacks sequence homology with other known nitrile-forming enzymes, it is structurally similar to pseudokinases. In vitro enzymatic reactions demonstrated that CalN specifically catalyzes nitrile formation through the adenylation of an amide substrate, calyculinamide A. In silico analyses and mutational experiments showed that CalN's structure features a unique insertion that plays critical roles in ATP recognition and the spatial coordination of catalytic residues. This study not only identifies a new family of nitrile-forming enzymes but also expands the variety of chemical reactions mediated by pseudokinases in nature.

Marine Toxins↗
PubMed2026

Multitargeted comparative evaluation suggests 2-Aoeobenoxmide shows favourable in silico binding compared to Tucatinib against ERα, HER2, AKT1, EGFR, and PIK3CA in breast cancer.

Breast cancer is a leading cause of cancer-related morbidity and mortality globally, with the WHO reporting approximately 2.3 million new cases and 685,000 deaths annually. Drug resistance in breast cancer complicates treatment, with mutations in critical proteins contributing to therapy failure. Key oncogenic proteins involved in breast cancer progression-namely ERα (a ligand-activated nuclear receptor; PDB: 1A52) and the kinase domains of HER2 (PDB ID: 3PP0), AKT1 (PDB ID: 4EJN), EGFR (PDB ID: 4I23) and PIK3CA (PDB ID: 7R9V)-are pivotal in tumour progression and resistance mechanisms. Targeting these proteins using multitargeted therapeutic strategies may overcome resistance by disrupting key signalling pathways involved in cell proliferation, survival, and metastasis. Such combinatorial approaches promise to improve treatment efficacy and patient outcomes in cases of resistant breast cancer. In this study, we performed multitarget docking on prepared and validated protein structures against the ZINC natural compound library using HTVS, SP, and XP, with pose validation using MM-GBSA. We identified 2-Aoeobenoxmide (2-[1-(2-amino-2-oxo-ethoxy)-6-oxo-benzo[c]chromen-3-yl]oxyacetamide, ZINC134008) with docking and MM-GBSA scores ranging from -8.162 to -10.327 kcal/mol and from -47.18 to -57.62 kcal/mol, respectively, and compared the results with the FDA-approved drug Tucatinib, which exhibited lower binding affinity scores. We further evaluated pharmacokinetic properties using QikProp and electronic properties using DFT (Jaguar) and compared the descriptors of 2-Aoeobenoxmide with those of Tucatinib and with accepted reference ranges. We also performed the WaterMap for 5 nanoseconds (ns), computed various energies, interactions and hydration sites, and the comparison suggests that 2-Aoeobenoxmide shows more favourable hydration-site displacement and binding interactions than Tucatinib. Additionally, a 100 ns MD Simulation has resulted in far less deviation, fluctuations, and intermolecular interactions than Tucatinib, suggesting stable protein-ligand interactions, while the binding free energy and total complex energy computed across 0-1000 frames of the MD trajectories indicate that 2-Aoeobenoxmide is a promising in silico candidate. Importantly, because the entire study is computational, the findings should be interpreted as in silico hypotheses, and experimental validation through in vitro and in vivo assays is warranted before any clinical translation is considered.

Humans↗
PubMed2026

No phenotypic resistance observed for most group-3 and -4 variants in Mycobacterium tuberculosis genes related to bedaquiline, clofazimine, delamanid, and pretomanid in a Central and West African context.

The interpretation of genetic variants' association (or not) with phenotypic resistance to newly introduced and repurposed antituberculosis drugs remains challenging, as many mutations detected by whole-genome sequencing (WGS) are classified as of uncertain significance (group 3) or not associated with resistance-interim (group 4) by the World Health Organization (WHO) mutation catalog v2. We evaluated the phenotypic impact of such variants on minimum inhibitory concentrations (MICs) for bedaquiline (BDQ), clofazimine (CFZ), delamanid (DLM), and pretomanid (PA) in Mycobacterium tuberculosis complex isolates from the multi-country DIAMA cohort in sub-Saharan Africa (SSA), which recruited RR/RS-TB patients naïve to these drugs. Among 1,475 isolates with available WGS data, 163 variants met eligibility criteria; due to viable strain unavailability, 89 isolates carrying 29 unique BDQ/CFZ-related and 60 unique DLM/PA-related variants were tested for MIC determination using broth microdilution. Additional structural modeling was performed to explore potential effects of amino-acid substitutions on protein stability. Among BDQ/CFZ-related variants, MICs above the critical concentrations (CCs) were consistently associated with mmpR5 variants, whereas variants in atpE, pepQ, and Rv1979c were not. DLM/PA variants (ddn, fbiA-D, and fgd1) were frequently detected as non-fixed populations, yet rarely yielding MIC values above the CC. Predicted structural destabilization showed no consistent association with MIC values or variant fixation status. Under the conditions tested, phenotypic resistance was not detected for most group 3 and 4 variants detected by WGS. Our data provide evidence from SSA to support improved interpretation of resistance-associated mutations for new and repurposed antituberculosis drugs.IMPORTANCEWhole-genome sequencing increasingly detects Mycobacterium tuberculosis complex mutations classified by the World Health Organization (WHO) mutation catalog v2 as group 3 variants of uncertain significance or group 4 variants not associated with resistance-interim, limiting reliable prediction of resistance to new and repurposed antituberculosis drugs. By generating minimum inhibitory concentration (MIC) data for such variants identified in a multi-country sub-Saharan African cohort, this study provides phenotypic evidence to support future refinement and expansion of the WHO mutation catalog v2. Notably, mmpR5 variants associated with elevated bedaquiline/clofazimine MICs were identified in eight isolates, suggesting that some patients in this cohort may have harbored pre-existing resistance-associated variants yet remained potentially eligible for bedaquiline-containing regimens. These findings contribute to improving the interpretation of genomic resistance data and strengthening surveillance of resistance to bedaquiline, clofazimine, delamanid, and pretomanid.

Mycobacterium tuberculosis↗