SWISS-MODEL: homology modelling of protein structures and complexes

A novel mannan-specific chimeric antigen receptor M-CAR redirects T cells to interact with Candida spp. hyphae and Rhizopus oryzae spores

Invasive fungal infections (IFIs) are responsible for elevated rates of morbidity and mortality, causing around of 1.5 million deaths annually worldwide. One of the main causative agents of IFIs is Candida albicans, and non-albicans Candida species have emerged as a spreading global public health concernment. Furthermore, COVID-19 has contributed to a boost in the incidence of IFIs, such as mucormycosis, in which Rhizopus oryzae is the most prevalent causative agent. The effector host immune response against IFIs depends on the activity of T cells, which are susceptible to the regulatory effects triggered by fungal virulence factors. The fungal cell wall plays a crucial role as a virulence factor, and its remodeling compromises the development of a specific T-cell response. The redirection of Jurkat T cells to target Candida spp. by recognizing targets expressed on the fungal cell wall can be facilitated using chimeric antigen receptor (CAR) technology. This study generated an M-CAR that contains an scFv with specificity to α-1,6 mannose backbone of fungal mannan, and the expression of M-CAR on the surface of modified Jurkat cells triggered a strong activation against Candida albicans (hyphae form), Candida tropicalis (hyphae form), Candida parapsilosis (pseudohyphal form), and Candida glabrata (yeast form). Moreover, M-CAR Jurkat cells recognized Rhizopus oryzae spores, which induced high expression of cell activation markers. Thus, a novel Mannan-specific CAR enabled strong signal transduction in modified Jurkat cells in the presence of Candida spp. or R. oryzae.

The LARP6 La module from Tetrabaena socialis reveals structural and functional differences from plant and animal LARP6 homologues

This study identified the LARP6 La Module from Tetrabaena socialis (T. socialis), a four-celled green algae, in an effort to better understand the evolution of LARP6 structure and RNA-binding activity in multicellular eukaryotes. Using a combination of sequence alignments, domain boundary screens, and structural modelling, we recombinantly expressed and isolated the TsLARP6 La Module to > 98% purity for in vitro biochemical characterization. The La Module is stably folded and exerts minimal RNA binding activity against single-stranded homopolymeric RNAs. Surprisingly, it exhibits low micromolar binding affinity for the vertebrate LARP6 cognate ligand, a bulged-stem loop found in the 5'UTR of collagen type I mRNA, but does not bind double-stranded RNAs of similar size. These result suggests that the TsLARP6 La Module may prefer structured RNA ligands. In contrast, however, the TsLARP6 La Module does not exhibit the RNA chaperone activity that is observed in vertebrate homologs. Therefore, we conclude that protist LARP6 may have both distinct RNA ligands and binding mechanisms from the previously characterized LARP6 proteins of animals and vascular plants, thus establishing a distinct third class of the LARP6 protein family.

Genetic variants in QRICH2 gene among Jordanians with sperm motility disorders

Sperm motility, a key determinant of male fertility, is often impaired by genetic variations affecting flagellar formation. The glutamine-rich protein 2 (QRICH2) gene encodes a protein essential for sperm flagella biogenesis and structural integrity. This study investigates genetic variations within exon 3 of the QRICH2 gene, identifying novel heterozygous variants associated with sperm tail-specific abnormalities and motility impairments. Among 34 individuals diagnosed with asthenozoospermia (ASZ) and 26 individuals with normal sperm parameters (NZ) from Jordan, eight unique heterozygous variants (c.123 G>T, c.133 G>C, c.138A>G, c.170A>C, c.189C>G, c.190T>C, c.195A>T, and c.204A>T) were exclusive to the ASZ group, while four variants (c.136 G>A, c.145A>C, c.179T>G, and c.180T>G) were found only in NZ. These variants were absent from major genetic databases, suggesting their potential novelty, while two variants (c.206C>T and c.189C>T) were linked to known SNP cluster IDs rs73996306 and rs1567790525, respectively. Four non-synonymous SNPs (c.136 G>A, c.145A>C, c.170A>C, and c.204A>T) were predicted to be functionally and structurally damaging, underscoring their significance. Additionally, five variants overlapped with previously reported mutation sites, indicating potential mutation hotspots. Statistical analysis revealed a significant association between QRICH2 mutations and tail defects (p < 0.021). These findings highlight the critical role of heterozygous QRICH2 mutations in mild-to-moderate ASZ, even in NZ individuals. Despite some carriers meeting WHO criteria for NZ, notable morphological abnormalities suggest the need for refined diagnostic benchmarks. Screening for QRICH2 mutations is essential for accurate molecular diagnosis and should be integrated into genetic counseling, particularly in regions like Jordan. Further research into the cumulative effects of heterozygous mutations and their environmental interactions is needed to expand our understanding of idiopathic male infertility and to enhance diagnostic and therapeutic strategies for male infertility.

Structural and functional analysis reveals the catalytic mechanism and substrate binding mode of the broad-spectrum endolysin Ply2741

The emergence of antibiotic-resistant bacteria has attracted interest in the field of endolysins. Here, we analyzed the diversity of Streptococcus endolysins and identified a new endolysin, Ply2741, that exhibited broad-spectrum bactericidal activity. Our results demonstrated that Ply2741 could effectively eradicate multidrug-resistant gram-positive pathogens in vitro and in vivo. Structural analysis revealed that the bactericidal activity of Ply2741 depends on the classic "Cys-His-Asn" catalytic triad. Site-directed mutagenesis results further identified that the conserved residue Gln29, located near the catalytic triad, also contributes to the lytic activity of Ply2741. Furthermore, the key residues (R189 and W250) in the Ply2741 cell wall binding domain (CBD) responsible for binding to peptidoglycan were revealed by molecular docking and fluorescence-activated cell sorting (FACS) analysis. Ply2741 demonstrates a broad lytic spectrum, with significant bactericidal activity against Enterococcus, Staphylococcus, and Streptococcus and species. To the best of our knowledge, we found that residue Gln29 participated in the lytic activity of endolysin for the first time. Additionally, we systematically elucidate the binding mode and key residues of the Ply2741CBD. This study proposes Ply2741 as a potential antibiotic substitute and provides a structural basis for the modification and design of endolysins.

Characterization and genomic insights into bacteriophages Kpph1 and Kpph9 against hypervirulent carbapenem-resistant Klebsiella pneumoniae

The increasing incidence of infections attributed to hypervirulent carbapenem-resistant Klebsiella pneumoniae (Hv-CRKp) is of considerable concern. Bacteriophages, also known as phages, are viruses that specifically infect bacteria; thus, phage-based therapies offer promising alternatives to antibiotic treatments targeting Hv-CRKp infections. In this study, two isolated bacteriophages, Kpph1 and Kpph9, were characterized for their specificity against the Hv-CRKp K. pneumoniae NUHL30457 strain that possesses a K2 capsule serotype. Both phages exhibit remarkable environmental tolerance, displaying stability over a range of pH values (4-11) and temperatures (up to 50°C). The phages demonstrate potent antibacterial and antibiofilm efficacy, as indicated by their capacity to inhibit biofilm formation and to disrupt established biofilms of Hv-CRKp. Through phylogenetic analysis, it has been revealed that Kpph1 belongs to the new species of Webervirus genus, and Kpph9 to the Drulisvirus genus. Comparative genomic analysis suggests that the tail fiber protein region exhibits the greatest diversity in the genomes of phages within the same genus, which implies distinct co-evolution histories between phages and their corresponding hosts. Interestingly, both phages have been found to contain two tail fiber proteins that may exhibit potential depolymerase activities. However, the exact role of depolymerase in the interaction between phages and their hosts warrants further investigation. In summary, our findings emphasize the therapeutic promise of phages Kpph1 and Kpph9, as well as their encoded proteins, in the context of research on phage therapy targeting hypervirulent carbapenem-resistant Klebsiella pneumoniae.

Sequence and taxonomic feature evaluation facilitated the discovery of alcohol oxidases

Recent advancements in data technology offer immense opportunities for the discovery and development of new enzymes for the green synthesis of chemicals. Current protein databases predominantly prioritize overall sequence matches. The multi-scale features underpinning catalytic mechanisms and processes, which are scattered across various data sources, have not been sufficiently integrated to be effectively utilized in enzyme mining. In this study, we developed a sequence- and taxonomic-feature evaluation driven workflow to discover enzymes that can be expressed in E. coli and catalyze chemical reactions in vitro, using alcohol oxidase (AOX) for demonstration, which catalyzes the conversion of methanol to formaldehyde. A dataset of 21 reported AOXs was used to construct sequence scoring rules based on features, including sequence length, structural motifs, catalytic-related residues, binding residues, and overall structure. These scoring rules were applied to filter the results from HMM-based searches, yielding 357 candidate sequences of eukaryotic origin, which were categorized into six classes at 85 % sequence similarity. Experimental validation was conducted in two rounds on 31 selected sequences representing all classes. Among these selected sequences, 19 were expressed as soluble proteins in E. coli, and 18 of these soluble proteins exhibited AOX activity, as predicted. Notably, the most active recombinant AOX exhibited an activity of 8.65 ± 0.29 U/mg, approaching the highest activity of native eukaryotic enzymes. Compared to the established UniProt-annotation-based workflow, this feature-evaluation-based approach yielded a higher probability of highly active recombinant AOX (from 8.3 % to 19.4 %), demonstrating the efficiency and potential of this multi-dimensional feature evaluation method in accelerating the discovery of active enzymes.

The major component of Heteractis magnifica sea anemone venom, RpIII, exhibits strong subtype selectivity for insects over mammalian voltage-gated sodium channels

Voltage-gated sodium channels (NaV) are molecular targets for the development of drugs for the treatment of diseases such as epilepsy, neuropathic pain, long QT syndrome, etc., as well as for insecticides. Therefore, the search for novel selective NaV channel ligands is relevant. Using amplicon deep sequencing of tentacle cDNA libraries from sea anemones Heteractis magnifica, 36 transcripts related to RpIII neurotoxin, a NaV channel modulators, were revealed. The recombinant RpIII was moderately toxic for mice (LD50 0.030 ± 0.004 mg/kg) but did not demonstrate any activity towards NaV in human SH-SY5Y cells. The toxin inhibited inactivation of heterologously expressed mammalian, insect, and arachnid NaV channels with higher specificity to insect channels. Cockroach (Blattella germanica) sodium channel BgNaV1 (EC50 of 2.4 ± 0.2 nM) and yellow fever mosquito (Aedes aegypti) channel AaNaV1 (EC50 of 1.5 ± 0.3 nM) were the most sensitive to RpIII, while mammals NaV had EC50 values above 100 nM except mNaV1.6 (EC50 of 43.8 ± 3.6 nM). The low nanomolar RpIII affinity to insect AaNaV1 may be explained by the extensive intermolecular contacts found by docking study. According to the predicted data, the toxin lands on the ion channel between voltage-sensing domain IV and pore domain I, also known as toxin site 3, followed by stabilizing the channels in the open state what was measured at electrophysiological experiments.

Construction of new thermostable MtLPMO9V in synergism with cellulases for efficient lignocellulosic hydrolysis

Lytic polysaccharide monooxygenases (LPMOs) can promote cellulose hydrolysis by disrupting its crystalline zone. This study focused on an uncharacterized thermophilic Myceliophthora thermophila LPMO (MtLPMO9V) in synergism with cellulases for efficient ligocellulosic hydrolysis. After MtLPMO9V was successfully expressed in P. pastoris GS115, the oxidative depolymerization of it was characterized by HPLC, HPAEC-PAD, and MALDI-TOF MS, indicating C4 oxidative cleavage activity. With combination of computer-aided design and MD simulation, MtLPMO9V was improved for a higher catalytic activity and thermostability by introduction of disulfide bonds, followed by point mutation. The mutant, A170C/A175C/Q120Y (M3), exhibited a remarkable enzymatic activity, increasing by 88 % as compared to the wild-type MtLPMO9V (WT), in which the catalytic efficiency (kcat/Km) was roughly 1.90 folds that of the WT. The M3 demonstrated broad applicability, not only showing synergism with the thermostable endoglucanase DtCelA for efficient high-temperature saccharification of cellulosic substrates, but also enhancing the saccharification of lignocellulosic substrates when combined with the commercial cellulase blend Celluclast 1.5L, where LPMO accounts for only 2-4 % of the cellulase mixture. This study provides valuable insights into engineering of new extreme LPMOs and also exhibits their potential applicability in development of cellulase-mediated lignocellulosic biorefinery industry.

Phytocompounds of Senecio candicans as potential acetylcholinesterase inhibitors targeting Alzheimer's disease: A structure-based virtual screening and molecular dynamics simulation study

Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by cognitive decline due to the accumulation of amyloid-beta plaques, neurofibrillary tangles, and decreased acetylcholine levels caused by acetylcholinesterase (AChE) activity. Current treatments using synthetic acetylcholinesterase inhibitors (AChEIs) provide only symptomatic relief and are associated with adverse effects, highlighting the need for safer and more effective alternatives. This study investigates the potential of phytoconstituents from the plant Senecio candicans as natural AChE inhibitors for AD treatment. Using structure-based virtual screening, molecular docking, and molecular dynamics simulations, we evaluated several compounds from Senecio candicans for their binding affinity, stability, and inhibitory activity against AChE. The findings identified compounds such as Estra-135(10)-trien-17β-ol and Vulgarone A, which demonstrated strong binding affinities and stable interactions with AChE, comparable to or surpassing the clinically used drug Donepezil. These phytoconstituents exhibited potential as effective AChEIs with potentially fewer side effects. The results underscore the therapeutic potential of plant-based molecules for drug discovery, offering a promising avenue for developing new treatments for neurodegenerative diseases. Combining phytochemical studies with computational methods provides a powerful approach to identifying novel therapeutic agents. This study suggests that phytoconstituents from Senecio candicans could serve as safer alternatives for managing AD. Further experimental validation and clinical studies are necessary to confirm these compounds' efficacy and safety, paving the way for innovative, plant-derived treatments for Alzheimer's disease.

The vacuole pH-related gene RcNHX2 affects flower color shift and Na+ homeostasis in roses

Rose (Rosa spp.) is one of the most famous ornamental plants in the world, and its commodity value largely depends on its flower color. The color of roses mainly depends on the composition and state of anthocyanins, and the vacuolar pH value is an important factor affecting the stability and state of anthocyanins. The vacuolar sodium/proton antiporters (NHXs) play important roles in the maintenance of cellular ion homeostasis and petal vacuolar pH. However, the NHX functions related to rose flower coloration remain relatively uncharacterized. In this study, we cloned and characterized the vacuolar pH-related gene RcNHX2, which encoded a vesicular cation/H+ antiporter protein. Phylogenetic sequence analysis revealed that RcNHX2 belongs to the vesicular NHX family of proteins. It is localized in the vesicular membrane, where it exerts its function. RcNHX2 was significantly differentially expressed in different color-presenting types of petals of roses, and it was particularly highly expressed in the blue-purple petals. The overexpression of RcNHX2 in Rosa hybrida 'Florentina' caused the pH to increase and the petal color to change from red to blue-purple. On the basis of virus-induced gene silencing, we determined that decreased RcNHX2 expression significantly reduces R. hybrida 'Blue For You' petal coloration. We indicated that RcNHX2 might be involved in the color shift to blue in roses. Moreover, it was observed that in the cells of the rose plants in which RcNHX2 was silenced, the Na+ homeostasis was affected. The results suggest that the vesicular Na+/H+ transporter, RcNHX2 gene, likely plays a crucial role in the blue color change and the maintenance of cellular Na+ homeostasis in roses. These findings offer valuable insights for the cultivation of blue rose.

A critical address to advancements and challenges in computational strategies for structural prediction of protein in recent past

Protein structure prediction has undergone significant advancements, driven by the limitations of experimental techniques like X-ray crystallography, NMR, and cryo-EM, which are costly and time-consuming. To bridge the gap between protein sequences and their structures, computational methods have emerged as essential tools. Traditional approaches such as homology modeling, threading, and ab initio folding made progress but often lacked atomic-level precision. The field has been revolutionized by deep learning-based models such as AlphaFold2, RoseTTAFold, and OpenFold, which have demonstrated unprecedented accuracy in predicting protein structures. These AI-driven models leverage vast datasets and neural networks to generate highly reliable structural predictions, sometimes rivaling experimental methods. This review explores the historical evolution of computational protein structure prediction, analyzing the strengths and weaknesses of state-of-the-art models. These models have broad applications in fields such as drug discovery, enzyme engineering, and disease-related protein modeling. However, challenges remain, including the need for extensive training data, computational resource requirements, and difficulties in modeling protein dynamics, intrinsically disordered regions, and protein-protein interactions. Future directions in the field include improving AI models to address current limitations, better integration with experimental techniques, and extending predictions to protein complexes and post-translational modifications. By continuing to refine these methods, computational protein structure prediction will further enhance biomedical research and therapeutic design, reshaping the landscape of structural biology and computational biophysics.

Phenyltins may pose a higher health risk to Indo-Pacific finless porpoises than butyltins

Organotin (OT) compounds are commonly used in antifouling paints, but can cause toxic effects in various marine organisms, including gastropods, amphibians, and teleosts. The effects of these chemicals on marine mammals remain largely unknown. We comprehensively investigated the accumulation patterns and health risks of six OTs in Indo-Pacific finless porpoises (Neophocaena phocaenoides) from the Pearl River Estuary (PRE), China, from 2007 to 2020. Six OTs were detected in all the finless porpoise samples, with tributyltin (TPT) and dibutyltin (DBT) being the dominant chemicals in the liver and muscle, respectively. The mean hepatic concentration of TPT (516.1 ng g-1 wet weight) exceeded the levels reported for cetaceans from other regions. Despite the observed decreasing trends of butyltins (BTs) in recent years, which aligns with the global restriction of OT-based antifouling paints since 2008, phenyltins (PTs) have continued to increase in porpoise tissues, suggesting continued deposition of PTs in the PRE. In vitro, the tissue-relative concentrations of TPT, tributyltin, and DBT-induced lipid disruption by activating the finless porpoise peroxisome proliferator-activated receptor α/γ (npPPARα/γ). In silico simulations further revealed a higher toxic potential of PTs than BTs on npPPARα/γ. Our results underscore the urgency for further monitoring and elimination of PTs in China.

Repurposing the amino-3,5-dicyanopyridine scaffold from adenosine receptor ligands to carbonic anhydrase activators

We are repurposing a set of imidazole-containing amino-3,5-dicyanopyridines, previously reported as adenosine receptor ligands, in the role of activators of human-expressed carbonic anhydrase isoenzymes (hCA I, II, VA, and VII) considered relevant to controlling brain functions. Our focus has been to identify new carbonic anhydrase activators (CAAs) as pharmacological tools useful to investigate the CA role in psychiatric and neurodegenerative disorders. All tested compounds were inactive at hCA II, highlighting a trend similar to that of the reference activator histamine. On the contrary, most of them showed different activation profiles at the other CAs tested. In particular, while compounds 13 and 24 had the lowest KA values at hCA VII (KA = 0.8 μM) and I (KA = 0.7 μM), respectively, derivatives 14 and 17 displayed the most effective and balanced activation profile at hCA I, VA, and VII, with KA values in the low micromolar range. The binding mode of compound 14 was investigated in silico using X-ray solved (hCA I and VII) and homology built (hCA VA) structures. Focusing our attention on drug-like compounds to find new pharmacological tools, the ADME properties of all derivatives were in silico calculated to investigate their drug-like behavior. Compound 17 emerged as a candidate, as it showed high oral availability and permeability of the gut-blood barrier, together with a good potential to cross the BBB.

Redesigning oxazolidinones as carbonic anhydrase inhibitors against vancomycin-resistant enterococci

The rise of vancomycin-resistant enterococci (VRE) as a leading cause of hospital-acquired infections underscores the urgent need for new treatment strategies. In fact, resistance has developed not only to vancomycin but also to other clinically used agents, such as daptomycin and linezolid. We propose a novel drug design approach merging tedizolid, a second-generation oxazolidinone used as an unapproved salvage therapy in clinical settings, with carbonic anhydrase inhibitors (CAIs) recently validated as functioning decolonization agents. These sulfonamide derivatives showed potent inhibition of the carbonic anhydrases from Enterococcus faecium, with KI values in the range of 14.6-598 nM and 63.2-798 nM against EfCAα and EfCAγ. Computational simulations elucidated the binding mode of these dual-action antibiotics to the peptidyl transferase center (PTC) of the 50S ribosome subunit and bacterial CAs. A subset of six derivatives showed potent PTC-related anti-enterococcal effects against multidrug-resistant E. faecalis and E. faecium strains with some compounds outperforming both the oxazolidinone and CA inhibitor drugs (MIC values in the range 1-4 μg/mL).

QpmH esterase from cotton rhizosphere bacteria: A novel approach for degrading quizalofop-p-ethyl herbicide

Within the rhizosphere, a rich population of biocontrol bacteria serves as a valuable resource for the biodegradation of environmental herbicides. This study aimed to evaluate rhizospheric microorganisms for their potential to degrade Quizalofop-p-ethyl, a widely used herbicide to control annual and perennial weeds in a variety of crops. A bacterial strain, MJ-8, isolated from cotton rhizosphere soil, demonstrated significant degradation activity. Based on morphological characteristics and 16S rRNA sequencing, the strain was identified as Priestia megaterium. Strain MJ-8 achieved a degradation rate of 90.65 % for Quizalofop-p-ethyl. Genomic analysis and amino acid sequence alignment revealed a key gene, designated QpmH, encoding a 30 kDa protein with strong biodegradation activity. Heterologous expression of the QpmH gene confirmed its role in Quizalofop-p-ethyl degradation. Molecular docking studies and structural modeling further elucidated the enzymatic mechanisms, supported by the analysis of their degradation products. Additionally, when QpmH gene was introduced into rice plants through Agrobacterium-mediated transformation, the resultant transformant conferred resistance to Quizalofop-p-ethyl at the recommended application dose. These findings highlight Priestia megaterium strain MJ-8 as a promising biological agent for sustainable herbicide management and position the QpmH gene as a potential new target for developing herbicide-resistant crops.

Development and evaluation of recombinant multi-epitopes vaccine against nervous necrosis virus

Capsid protein (CP) is the antigen of nervous necrosis virus (NNV), a fatal microorganism for almost marine fishes. Antigen epitope is a special chemical group in an antigen molecule that determines the specificity of the antigen, usually consisting of 5-15 amino acid residues. However, the antigen epitope of NNV antigen remains unclear. In this study, using immunoinformatic method, we analyzed the antigen epitope of CP and designed a multi-epitopes vaccine of NNV (PA). Furthermore, we evaluated the immune responses induced by PA vaccine. The results showed that three cytotoxic T lymphocyte epitopes and six B-cell lymphocyte epitopes were predicted, with high antigenicity, non-allergen, and non-toxin. Based on these epitopes, a multi-epitopes vaccine of NNV (PA) was designed and prepared. After immunization, the mRNA expression levels of IL-1β, TNF-α, CD4, CD8, MHC-Ⅰ, and MHC-Ⅱ in PA group were significantly up-regulated. Moreover, it has been proven that PA could significantly activate antigen presenting cells. Importantly, PA could induce similar levels of antibodies secretion and immune protection, compared to CP group. The survival rate reached 77.22 % in PA group. This study provides a cheap and effective strategy for aquatic vaccine design, which will be beneficial in application to development of vaccine in aquaculture industry.

Exploring evolutionary use of single residue switches for alternative product outcome in class II diterpene cyclases

Class II diterpene cyclases (DTCs) define the widespread labdane-related diterpenoids. These are particularly prevalent in plants due to the requisite production of gibberellin (GA) phytohormones, specifically from gene duplication and neofunctionalization of the relevant DTC. Alteration of product outcome can be predicted/engineered to some extent by changes in the ancestral histidine-asparagine catalytic base dyad found in the ent-copalyl pyrophosphate (ent-CPP) synthases (CPSs) involved in GA biosynthesis. It has been shown such changes can switch product outcome in CPSs, with substitution of alanine for either leading to incorporation of water - i.e., production of 8α-hydroxy-ent-labda-13-en-15-yl pyrophosphate (ent-LPP), while replacing the histidine with tyrosine leads to production of a rearranged product - i.e., ent-kolavenyl pyrophosphate (ent-KPP). Indeed, native ent-KPP synthases from dicots with such substitution have been found, and restoration of the ancestral residue results in production of ent-CPP. Observation of a similar ent-KPP synthase and, strikingly, an ent-LPP synthase with serine in place of the asparagine, along with another DTC with such substitution but still producing ent-CPP, was recently made in non-seed plants. Here the role of these substitutions was examined by ancestral residue restoration. Notably, while this led to the production of ent-CPP in the first two concordant cases, in the latter incongruent DTC this had little effect. This presumably reflects extended adaptation, consistent with its more distant phylogenetic relationship to those from GA biosynthesis. This demonstrates both the utility but also limitations of the ability of changes to the ancestral catalytic base dyad to affect product outcome.

Evaluation of the intrinsic antibacterial and antibiotic potentiating activity against antibiotic resistance in Staphylococcus aureus and inhibition of the NorA and MepA efflux pumps by a hydrazone derivative of isoniazid

Hydrazones are organic compounds with promising antimicrobial properties, particularly in the fight against resistant microorganisms. The aim of this study was to synthesize and evaluate the antibacterial activity of the hydrazone derivative of isoniazid N'-[[4-({[(pyridin-4-yl)formamido]imino] methyl)phenyl]methylidene]pyridine-4 carbohydrazide (BISHDZHI) against Staphylococcus aureus overexpressing NorA and MepA efflux pumps. The broth microdilution methodology was used in the microbiological tests to evaluate the antibacterial potential of the BISHDZHI compound and its ability to inhibit efflux pump resistance mechanisms. To elucidate the mechanism of action, molecular docking simulations were conducted to assess the binding affinity of BISHDZHI to the NorA and MepA efflux pumps. Minimum inhibitory concentration (MIC) tests showed that BISHDZHI in association with norfloxacin moderately reduced the MIC of the antibiotic, indicating the enhancement of its efficacy. However, an antagonistic effect was observed in combination with ethidium bromide, suggesting that the compound does not directly inhibit bacterial efflux pumps, but may act on other intracellular targets, such as the enzyme topoisomerase IV. The docking studies revealed strong interactions between BISHDZHI and key amino acid residues within the efflux pumps, particularly Tyr225, Val302, and Phe306 in NorA and Leu59, Phe280, and Tyr276 in MepA. The docking scores indicated favorable binding energies, suggesting potential inhibitory effects on efflux activity. This study highlights the potential of the hydrazone BISHDZHI as a promising candidate for treating infections caused by the bacterium Staphylococcus aureus.

Evolutionary insights and poly(I:C)-induced changes in expression and m6A modifications of il17ra and il17rc in Miichthysmiiuy

Interleukin-17 receptor A (IL17RA) and IL17RC form a receptor complex critical for initiating IL-17A-mediated immune responses, a hallmark of T helper 17 (Th17) cells. In this study, il17ra and il17rc were identified in miiuy croaker (Miichthys miiuy) and bioinformatics analysis revealed their evolutionary and structural conservation, underscoring their roles in immunity. However, there has been little research on the IL-17 receptor family from the perspective of N6-methyladenosine (m6A) modifications. Using methylated RNA immunoprecipitation sequencing (MeRIP-seq), we identified strong m6A modifications on the last exons of il17ra and il17rc, validated by MeRIP-PCR. Poly(I:C) stimulation significantly upregulated il17ra and il17rc expression, while reducing their m6A modification levels, implicating these changes in antiviral immunity. Interestingly, cycloleucine (CL), a well-known methylation inhibitor, did not alter the expression of il17ra and il17rc but promoted the nuclear-to-cytoplasmic transport of il17ra mRNA, potentially influencing its translation process. These findings provide valuable insights into the regulatory roles of m6A modifications in il17ra and il17rc function and highlight their importance in the antiviral immune response.

Unified Aedes aegypti Protein Resource Database (UAAPRD): An Integrated High-Throughput In Silico Platform for Comprehensive Protein Structure Modeling and Functional Target Analysis to Enhance Vector Control Strategies

A comprehensive examination of Aedes aegypti's proteome to detect key proteins that can be targeted with small molecules can disrupt blood feeding and disease transmission. However, research currently only focuses on finding repellent-like compounds, limiting studies on identifying unexplored proteins in its proteome. High-throughput analysis generates vast amounts of data, raising concerns about accessibility and usability. Establishing a dedicated database is a solution, centralizing information on identified proteins, functions, and modeled structures for easy access and research. This study focuses on scrutinizing key proteins in A. aegypti, modeling their structures using RaptorX standalone tool, identification of druggable binding sites using BiteNet, validating the models via Ramachandran plot studies and refining them via 50-ns molecular dynamic simulations using Schrodinger Maestro. By analyzing ~ 18 k proteins in the proteome of A. aegypti in our previous studies, all proteins involved in the light and dark circadian rhythm of the mosquito, inclusive of proteins in blood feeding, metabolism, etc. were chosen for the current study. The outcome is UAAPRD, a unique repository housing information on hundreds of previously unmodeled and un-simulated mosquito proteins. This robust MYSQL database ( https://uaaprd.onrender.com/user ) houses data on 309 modeled & simulated proteins of A. aegypti. It allows users to obtain protein data, view evolutionary analysis data of the protein categories, visualize proteins of interest, and send request to screen against the pharmacophore models present in UAAPRD against ligand of interest. This study offers crucial insights for developing targeted studies, which will ultimately contribute to more effective vector control strategies.

Ecological divergence of marine bacteria Alteromonas mediterranea

Alteromonas mediterranea, originally designated as A. macleodii, is a deep-sea ecotype that plays an important ecological role in the ocean. However, a comprehensive understanding of their biogeographic distribution and evolutionary histories remains limited. In this study, our analysis indicated that A. mediterranea members could adapt contrasting marine ecosystems and flourish in nutrient-rich habitats such as feces and coral reefs. No significant correlations between the relative abundance of A. mediterranea members and the environmental variables were identified. Phylogenetic analysis and geographic patterns of A. mediterranea strains suggested that they could be clustered into two clades (clade Ⅰ and clade Ⅱ). In contrast, many distinct genomic traits exist between these clades, such as the complete genes encoding cytochrome o ubiquinol oxidase only involved in clade Ⅱ. Genes were more likely to be lost in the evolutionary history of A. mediterranea relatives. Gene loss might be a major force in all phylogenetic groups driving the distinct clades. Adaptation to different biotopes resulted in the functional differentiation of A. mediterranea members, with the loss of genes encoding carbohydrate-active enzymes. Genes acquired horizontally from unclassified bacteria, and Proteobacteria represented by Gammaproteobacteria played key roles in the functional diversification of A. mediterranea in marine habitats. Given these data, these results are useful for information supplementation of A. mediterranea strains, particularly for making significant advances in understanding marine microbial ecology within different clonal frames using genome-wide recruitments.

Pleiotropic signaling of single-chain thyrostimulin (GPB5-GPA2) on homologous glycoprotein hormone receptors (ScFSHR, ScLHR, ScTSHR) in the elasmobranch Scyliorhinus canicula reproduction

The pituitary glycoprotein hormones (GPHs) control several physiological processes in vertebrates such as reproduction and metabolism. They include the luteinizing hormone (LH), the follicle-stimulating hormone (FSH), and the thyroid-stimulating hormone (TSH), which activate their cognate leucine-rich repeat G protein-coupled receptors (LGRs), LHR, FSHR, and TSHR. Each GPH consists of a common α subunit and a specific βFSH, βLH or βTSH subunit. More recently, two supplementary GPH proteins, GPA and GPB, were identified in nearly all bilaterians and are the ancestors of the pituitary GPH α- and β-subunits, respectively. Chondrichthyans (holocephalans and elasmobranchs), the sister group of bony vertebrates, are the most ancient clade to possess diversified GPH subunits. In the present study, GPA2, GPB5, TSHβ2, but not TSHβ1, and TSHR sequences have been identified in several elasmobranch genomes, and their 3D models were analyzed. Functional hormone-receptor interactions were studied in the small-spotted catshark (Scyliorhinus canicula) and showed that conditioned media from cells expressing the recombinant single-chain ScGPB5-ScGPA2 were more effective than independent subunits in activating ScTSHR, ScFSHR, and ScLHR. Expression profiles were analyzed by real-time PCR, in situ hybridization, and immunohistochemistry along the male genital tract, other male and female tissues, and female tissues. A broader tissue distribution expression was observed for tshr and gpa2 than for gpb5, which was mainly observed in the testes. In testis, expression of tshr and gpb5 by Sertoli cells and of gpa2 by germ cells suggested paracrine/autocrine functions of GPA2/GPB5/GPHR signaling during spermatogenesis. This study complements the data on GPA2 and GPB5 by studying a chondrichthyan of phylogenetic interest for understanding the evolution of endocrine regulation in vertebrates.

Identification, characterization, and functional verification of a novel fish-egg lectin (FEL) from the golden pompano, Trachinotus ovatus

Lectins play important roles in the innate immune response and therefore are of great interest for immunologists. Although different families of lectins have been increasingly documented in various fish species, our current understanding of fish-egg lectins (FELs) is still in paucity. In this study, a novel FEL (ToFEL) was identified in the commercially important marine fish golden pompano (Trachinotus ovatus) through transcriptomic screening. In addition to bioinformatic characterization, the expression of ToFEL in different tissues and upon pathogenic challenge were profiled. Moreover, the binding capacity of ToFEL to five bacteria and the agglutinating activity of ToFEL against bacteria as well as blood and sperm cells of donor species with and without Ca2+ were assessed using the recombinant T. ovatus FEL (rToFEL). Our results demonstrated that ToFEL had an open reading frame (ORF) of 786 bp, which encodes a putative protein with 261 amino acids including a signal peptide consists of 19 amino acids. In addition to harboring three typical TECPR domains, a Ca2+-binding site was also identified in ToFEL. The ToFEL was shown to be highly homology to FELs of other fish species investigated, especially to its close relatives Seriola dumerili and S. lalandi. The expression of ToFEL was detected in all the ten tissues examined (predominantly in gill, liver, and ovary) under normal condition and was significantly induced upon pathogenic challenge. In addition, in the presence of Ca2+, the rToFEL exhibited strong binding and agglutinating activity against both gram-positive and gram-negative bacteria as well as blood and/or sperm cells of donor species. Collectively, our data indicate that ToFEL is a constitutive and inducible acute-phase immune molecule of T. ovatus in response to a broad-spectrum alien substances.

Biomolecular conformational changes and transient druggable binding sites through full-length AMPK molecular dynamics simulations

AMPK (AMP-activated protein kinase) is a crucial signaling protein found in essentially all eukaryotic organisms and acts as an energy sensor. When activated by metabolic stress, AMPK phosphorylates a variety of molecular targets, altering enzyme activity and gene expression to regulate cellular responses. In general, in response to low intracellular ATP levels (high ADP:ATP ratio), AMPK triggers the activation of energy-producing pathways while simultaneously inhibiting energy-consuming processes. Recent studies have established a connection between molecular pathways involved in sensing energy and potential for extending longevity. AMPK indirect activator compounds have shown a potential strategy to obtain an anti-aging biological activity. This study explores the conformational changes and transient druggable binding pockets over the 1 μs trajectory of molecular dynamics simulations to comprehend the behavior of main domains and allosteric drug and metabolite (ADaM) site. The described conformations of the apo-ADaM site suggest an important influence of specific residues on the cavity volume variations. A clustering set of representative AMPK conformations allowed to identify the more favorable binding site volume and shape at the protein apo form, including the carbohydrate-binding module (CBM) region which exhibited a stable movement near the ADaM site of the alpha-subunit. The identification of gamma-subunit transient druggable binding pocket CBS3 during the microscale time trajectory simulations also offers valuable insights into structure-based AMP-mimetic drug design for AMPK activation.

Association and binding interaction between per- and polyfluoroalkyl substances and maternal thyroid hormones: A case study based on a prospective birth cohort in Wuxi, China

BACKGROUND AND AIM

The relationship between prenatal exposure to per- and polyfluoroalkyl substances (PFASs), a well-known endocrine disruptor, and thyroid hormones (THs) levels remains unclear. Therefore, this study aimed to investigate this relationship in a birth cohort during the second trimester.

METHOD

This prospective study included 562 pregnant women in the Wuxi Birth Cohort from 2019 to 2021 and quantified the serum concentrations of 23 PFASs and 5 THs. Multiple statistical models were used to assess the associations between individual or combined PFASs concentrations and THs, while molecular docking simulated the interactions between PFASs and four thyroid-related proteins.

RESULTS

The median concentration of ∑23PFASs was 71.91 ng/mL, with perfluorovaleric acid (PFPeA) (18.13 ng/mL) emerging as the predominant PFAS. Most PFASs were negatively associated with maternal free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels, whereas perfluorobutane sulfonate (PFBS) was positively correlated with TSH levels. A similar trend was observed in the weighted quantile sum (WQS) model, in which combined PFASs exposure was inversely associated with the FT4 and TSH levels. Molecular docking results showed that compared with TH natural ligand thyroxine (T4), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl- PFESA) exhibited relatively high binding affinity with thyroid-related proteins (-6.6 to -9.8 kcal/mol vs. T4: -5.6 to -8.6 kcal/mol). Furthermore, PFASs with medium chain lengths and sulfonic acid groups exhibited enhanced protein-binding properties.

CONCLUSION

PFASs exposure may affect THs homeostasis during pregnancy. Moreover, different types and concentrations of PFASs have different effects on THs in the maternal serum.

Synthesis of Benzo[h]quinoline derivatives and evaluation of their insecticidal activity against Culex pipiens L. larvae

A new series of pyrrolinone and hydrazone derivatives containing a benzo[h]quinoline core was synthesized and evaluated for their insecticidal activity against Culex pipiens larvae. The synthesis involved condensation of acid hydrazide, obtained from a 2(3H)-furanone, with a variety of carbonyl compounds leading to the desired candidates. The larvicidal bioassays of the prepared compounds revealed that several derivatives exhibited potent activity, with pyrrolinone 6 showing the highest efficacy (LC50 = 0.4 μg/mL), surpassing the reference insecticide chlorpyrifos. Molecular docking and molecular dynamics (MD) simulations supported these findings, showing strong and stable binding of the synthesized compounds, particularly compound 6, to key mosquito neuroreceptors such as acetylcholinesterase (AChE). The structure-activity relationship (SAR) analysis highlighted the impact of functional groups on insecticidal potency. Additionally, in silico pharmacokinetic predictions indicated favorable ADME profiles for several derivatives, emphasizing their potential as effective mosquito control agents. It is hoped that this study might provide insights into the design of new benzo[h]quinoline-based insecticides contributing to addressing the challenge of insecticide resistance in mosquito populations by forming structures that could target multiple neuroreceptors.

Modification of carbonyl reductase based on substrate pocket loop regions alteration: an application for synthesis of duloxetine chiral intermediate in high efficiency

Duloxetine, a prominent 5-hydroxytryptamine norepinephrine reuptake inhibitor, is deployed mainly in the management of adult depression, showcasing minimal side effects, swift therapeutic onset, and a robust safety profile. Ethyl (S)-3-hydroxy-3-(2-thienyl)propionate ((S)-HEES) is the crucial chiral intermediate for duloxetine production. Asymmetric synthesis of (S)-HEES using carbonyl reductase as the biocatalyst has exhibited advantages including mild reaction conditions, high catalytic efficiency and environmental friendliness. In the present study, a loop region alteration strategy was developed to screen for a carbonyl reductase for (S)-HEES synthesis and EaSDR6 from Exiguobacterium sp. s126 was identified with considerable catalytic performance and broad substrate adaptability. Site-directed mutagenesis was subsequently performed, Mut-R142A/N204A was identified with a 3.6-fold enhancement in activity relative to the wild-type EaSDR6. The mutant kcat value was 52.5 s-1, 2.9-fold compared to the wild type, and the total catalytic efficiency (kcat/KM) was 24.9 mM-1 s-1, 1.9-fold higher than the wild type. The n-butyl acetate-aqueous biphasic bioreaction system was established for the asymmetric synthesis of (S)-HEES with the conversion of ethyl 3-oxo-3-(2-thienyl)propionate (KEES) of 90.2%, the product e.e. of > 99% after 8 h reaction at a substrate concentration of 200 g/L. The spatiotemporal yield reached 22.5 g/(L·h), which was higher than the ever reports about (S)-HEES biosynthesis. The present research provides new knowledge and technology for the construction of stereoselective carbonyl reductase and the green biosynthesis of chiral alcohol pharmaceutical intermediates.

RNA chaperone Hfq promotes the growth of Yersinia enterocolitica in refrigerated foods

Yersinia enterocolitica is a major foodborne pathogen causing yersiniosis, a significant zoonotic infection. Its unique cold tolerance makes it a potential threat to the safety of cold chain food. The RNA-binding protein Hfq is known to be involved in bacterial stress regulation, but its role in the cold tolerance of Y. enterocolitica remains unclear. Based on gene knockout and complementation, this study revealed that deleting the hfq gene disrupted the exponential growth phase of Y. enterocolitica under low-temperature conditions, leading to a biphasic growth phenomenon. Additionally, through the construction of point mutants, it was found that the critical amino acid sites for cold-tolerance regulation of Hfq in Y. enterocolitica are located on the distal and proximal surfaces. Further studies found that the biphasic growth process of the hfq deletion mutant was affected by the initial bacterial concentration and exogenous fatty acids. RT-qPCR results showed that Hfq regulation may affect the synthesis of branched-chain amino acids, and TCA cycle-related genes were significantly up-regulated during the second exponential growth. Studies based on milk and meat have shown that Hfq can promote the low-temperature growth of Y. enterocolitica in the food matrix. Our study provides evidence that Hfq-dependent regulation of energy metabolism is critical for cold tolerance in Y. enterocolitica. This study highlights the importance of Hfq in regulating cold tolerance in Y. enterocolitica and discusses its potential regulatory mechanism.

Targeted codelivery of nitric oxide and hydrogen sulfide for enhanced antithrombosis efficacy

Thrombosis is a leading cause of mortality worldwide. As important gaseous signaling molecules, both nitric oxide (NO) and hydrogen sulfide (H2S) demonstrate antiplatelet and anticoagulant functions, but little attention has been given to their synergistic effect and the underlying mechanism. In the present study, we developed an NO/H2S codelivery system based on enzyme prodrug therapy (EPT) strategy in which the prodrugs are specifically recognized by the engineered β-galactosidase. Targeted codelivery of NO and H2S in vivo was demonstrated by near-infrared fluorescence imaging and confirmed by measuring plasma and tissue levels; as a result, the side effects caused by systemic delivery, such as bleeding time, were reduced. Delivery of an optimized combination of NO and H2S with a low combination index (CI) results in a synergistic effect on the inhibition of platelet adhesion and activation. Mechanistically, NO and H2S cooperatively enhance the cGMP level through redox-based posttranslational modifications of phosphodiesterase 5A (PDE5A), which leads to activation of the cGMP/PKG signaling pathway. Furthermore, targeted codelivery of NO and H2S demonstrates enhanced therapeutic efficacy for thrombosis in two mouse models of FeCl3-induced arterial thrombosis and deep vein thrombosis. Collectively, these results confirm the synergistic efficacy of NO and H2S for antithrombotic therapy, and the codelivery system developed in this study represents a promising candidate for clinical translation.

Phosphorylation of ITIM motifs drives the structural transition of indoleamine 2,3-dioxygenase 1 between enzymatic and non-enzymatic states

Indoleamine 2,3-dioxygenase 1 (IDO1) is the rate-limiting enzyme in tryptophan metabolism that plays a central role in immune regulation across a range of diseases, including cancer. Beyond its enzymatic role, IDO1 has a non-enzymatic function that remains poorly understood. This study explores how phosphorylation of immunoreceptor tyrosine-based inhibitory motifs (ITIMs) modulates IDO1's structural dynamics and functional states. Using molecular dynamics simulations and structural analysis, we show that phosphorylation acts as a molecular switch, inducing conformational changes that regulate heme-binding, remodel specific loop regions, and govern protein-protein interactions with SHP1, SHP2, and SOCS3. Notably, Tyr249 phosphorylation inhibits enzymatic activity by compacting the heme-binding pocket, creating steric hindrance that prevents cofactor binding. In contrast, Tyr111 phosphorylation enhances interactions with SHP1 or SHP2 proteins by embedding their C-terminal regions into the heme-binding pocket, also obstructing heme binding. Furthermore, Tyr249 phosphorylation promotes SOCS3 binding through the formation of a unique loop structure near the phosphorylation site. These findings provide a detailed mechanistic framework for understanding how ITIM phosphorylation orchestrates IDO1's functional transitions, effectively balancing its enzymatic and non-enzymatic functions.

Molecular mimicry in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases (ARDs) are a heterogeneous group of conditions characterized by excessive and misdirected immune responses against the body's own musculoskeletal tissues. Their exact aetiology remains unclear, with genetic, demographic, behavioural and environmental factors implicated in disease onset. One prominent hypothesis for the initial breach of immune tolerance (leading to autoimmunity) is molecular mimicry, which describes structural or sequence similarities between human and microbial proteins (mimotopes). This similarity can lead to cross-reactive antibodies and T-cell receptors, resulting in an immune response against autoantigens. Both commensal microbes in the human microbiome and pathogens can trigger molecular mimicry, thereby potentially contributing to the onset of ARDs. In this review, we focus on the role of molecular mimicry in the onset of rheumatoid arthritis and systemic lupus erythematosus. Moreover, implications of molecular mimicry are also briefly discussed for ankylosing spondylitis, systemic sclerosis and myositis.

Comprehensive in silico characterization of nonsynonymous SNPs in the human ezrin (EZR) gene and their role in disease pathogenesis

Ezrin (EZR) is a crucial linker between the actin cytoskeleton and the plasma membrane. It interacts with proteins involved in cancer-related signaling pathways. To assess the impact of nonsynonymous single nucleotide polymorphisms (nsSNPs) on EZR structure and function, we employed bioinformatics tools (SIFT, PolyPhen-2, PROVEAN, PhD-SNP, SNPs&GO, SuSPect, and FATHMM) and identified deleterious variants. Stability analyses using MUpro, mCSM, I-Mutant 2.0, and DynaMut2 revealed six destabilizing nsSNPs (F240S, H288D, I248T, L59Q, L125S, and L225P). Structural modeling using HOPE, MutPred2, AlphaFold, Swiss-Model, and protein-protein docking using HADDOCK 2.4 assessed the impact on the EZR-EBP50 complex. Binding free energy calculations, salt bridge analysis, and interface residue mapping further confirmed that the L225P, F240S, and I248T mutations significantly impaired EZR-EBP50 interaction, potentially disrupting key signaling pathways. Molecular dynamics simulations indicated that mutant EZR proteins exhibited reduced stability, flexibility, and hydrogen bonding. This first comprehensive in silico analysis of EZR highlights pathogenic nsSNPs that may contribute to disease progression. These findings provide a foundation for experimental validation and may inform targeted therapies for EZR-related pathologies.

Naringenin as potentiator of norfloxacin efficacy through inhibition of the NorA efflux pump in Staphylococcus aureus

Bacterial resistance is a major challenge in the treatment of Staphylococcus aureus infections, with efflux mechanisms highlighted as reducing the efficacy of antibiotics. In this study, we investigated the potential of naringenin, a natural flavonoid, as an antibacterial agent and efflux pump inhibitor in S. aureus strains 1199 and 1199B. The studies used minimum inhibitory concentration (MIC) assays, ethidium bromide (EtBr) fluorescence emission enhancement assays, cell membrane permeability assays, and in silico molecular docking and ADME prediction assays. Naringenin showed no relevant antibacterial activity (MIC ≥1024 μg/mL). However, it potentiated the effect of norfloxacin and EtBr, reducing their MICs and increasing the fluorescence emission of EtBr, suggesting a possible inhibition of the NorA efflux pump. Bacterial membrane permeability was not significantly affected. Molecular docking assays indicated that naringenin interacts with the chlorpromazine binding site and has more favorable affinity energy than the chlorpromazine-NorA complex. ADME prediction showed favorable physicochemical properties, good oral absorption, metabolic stability and central nervous system safety. Therefore, naringenin demonstrates the potential to reverse the efficacy of norfloxacin in S. aureus by associating with efflux inhibition through effective interactions with the NorA protein, suggesting its therapeutic potential against bacterial resistance.

G462S substitution of AaCYP51 confers moderate resistance to tebuconazole in Alternaria alternata

BACKGROUND

Tobacco brown spot (TBS) caused by Alternaria alternata is one of the most common diseases of tobacco in China, resulting in large loss in yield and quality. Demethylation inhibitors (DMIs) such as tebuconazole are commonly used pesticides to control TBS. However, their control effect has shown a downward trend in recent years. In this study, the occurrence and molecular mechanism of resistance to tebuconazole in Alternaria alternata were analyzed.

RESULTS

The resistance of 63 strains of Alternaria alternata to tebuconazole was investigated with the concentration of 5 and 20 μg/mL as the identification standard, and the resistance frequency was as high as 93.65%. It was found that the target mutation from G to S at the 462nd amino acid position of CYP51 was the cause of moderate resistance to tebuconazole in A. alternata. Molecular docking analysis further confirmed that the G462S mutation of AaCYP51 decreased the binding affinity of tebuconazole to CYP51. The artificial AaCYP51-G462S transformants based on wild-sensitive GZA-24 showed resistance to tebuconazole and cross-resistance to metconazole and prothioconazole. In the present investigation, the virulence of the CYP51-G462S mutant was reduced, while mycelial growth, sporulation, and conidial germination did not change in comparison with the progenitor strain GZA-24. In addition, the mutants containing the G462S mutation in AaCYP51 exhibited decreased sensitivity to high osmotic stress stimulated by 1 M NaCl, and the capacity to respond to cell wall- and cytomembrane-damaging agents did not change in the mutants.

CONCLUSION

The G462S substitution of CYP51 is the main factor for the moderate resistance to tebuconazole in A. alternata and mechanisms other than CYP51-target mutation might be involved in tebuconazole lowly resistant isolates. © 2025 Society of Chemical Industry.

Genetic variations in the IDUA gene in Tunisian MPS I families: Identification of a novel microdeletion disrupting substrate binding and structural insights

Background

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by a deficiency in alpha-L-iduronidase (IDUA), leading to the accumulation of glycosaminoglycans. MPS I presents with a broad spectrum of clinical phenotypes, ranging from severe to mild. This study aimed to identify genetic mutations in the IDUA gene among Tunisian families and assess their structural and functional implications.

Patients and methods

Genomic DNA was extracted from blood samples of four patients including two siblings from three Tunisian families. Polymerase chain reaction (PCR) followed by Sanger sequencing was performed to identify mutations in the IDUA gene. Bioinformatics tools, including the SWISS-MODEL server and DynaMut, were used for structural modeling and to predict the impact of the mutations on protein stability and flexibility.

Results

Two mutations in the IDUA gene were identified. A novel deletion mutation p.His356_Gln362del was discovered in two patients with severe MPS I phenotypes, while a previously reported missense mutation p.Pro533Arg was found in two patients with intermediate and mild phenotypes. Structural analysis revealed that the novel deletion disrupts the protein's substrate-binding site. This deletion causes structural deformation and leads to the elimination of the substrate binding site, resulting in a complete loss of enzymatic activity.The missense mutation p.Pro533Arg affects the stability and flexibility of the protein, likely reducing substrate affinity. This substitution results in the introduction of a bulkier amino acid, requiring more space in the contact region between the β-sheet structure and the substrate-bound helix.

Conclusion

This study reports a novel deletion mutation in the IDUA gene in Tunisian MPS I patients, alongside a previously described mutation. The findings enhance understanding of the molecular basis of MPS I and provide insights into the structural effects of these mutations, which could aid in future diagnosis and therapeutic strategies. Future studies should explore the prevalence of the reported mutations in larger cohorts and investigate targeted therapies, such as pharmacological chaperones, to rescue enzymatic activity in patients carrying such mutations.

Microbial tannases: biosynthesis, purification, characterization and potential industrial applications

Tannases are a family of esterases that catalyze the hydrolysis of ester and depside bonds present in hydrolyzable tannins to release glucose and gallic acid. This enzyme is widely spread in animals, plants, and microbes. In particular, fungi and bacteria are the major sources of tannase. In recent years, this enzyme has drawn the attention of investigators owing to its widespread emerging applications in different food, beverage, animal feed, pharmaceutical, and tannery effluent degradation processes. During the last decade, over-expression of the tannase gene and structural activity has gained momentum. This research focused on microbial tannases, which have sparked interest due to their various properties. The current study investigates the sources of tannase-producing microorganisms, the mechanisms of tannin metabolism, and the microbe's degradation of natural tannins. Furthermore, researchers proposed tannase's biochemical properties, cloning, expression, and structural construction. This review will help better understand microbial tannases for several important industrial and environmental applications.

Discovery of Potential Anthelmintic Agents Against Gyrodactylus kobayashii Through Computer-Aided Drug Design and In Vivo Evaluation

Monogeneans are ectoparasitic flatworms causing significant economic losses in aquaculture. This study aimed to identify potential anthelmintic agents against these parasites by integrating computer-aided drug design (CADD) and in vivo evaluation. The β-tubulin gene, a well-established anthelmintic target, was cloned from Gyrodactylus kobayashii and its three-dimensional structure was generated using homology modelling. Virtual screening of 2319 FDA-approved drugs and nine common benzimidazoles against the modelled β-tubulin identified several promising compounds with low binding energy. Subsequent in vivo anthelmintic efficacy and acute toxicity assays in goldfish revealed etravirine as a potent candidate with an EC50 value of 0.55 mg/L and a therapeutic index (TI) greater than 18.18. This favourable safety profile highlights etravirine's potential for controlling monogenean infections in aquaculture. Flubendazole and mebendazole also demonstrated potent anthelmintic activity, with EC50 values of 0.022 and 0.023 mg/L and therapeutic indices exceeding 45.45 and 43.48, respectively. Molecular dynamics simulations confirmed stable binding modes for flubendazole and mebendazole with β-tubulin, providing mechanistic insights into their anthelmintic activity. Overall, this study demonstrated the utility of CADD in identifying potential therapeutic agents against monogenean and underscored the importance of β-tubulin as a key target for anthelmintic therapy, contributing to the development of sustainable aquaculture practices.

Overexpression of the GmERF071 gene confers resistance to soybean cyst nematode in soybean

Soybean cyst nematode (SCN) is one of the most harmful pests, causing major reductions in soybean yield globally. The validation and functional characterization of SCN resistance genes are crucial to improving soybean yield worldwide. Herein, we describe an SCN resistance gene, GmERF071 (Glyma.19g262700). GmERF071 is a hydrophilic, unstable protein with an AP2/ERF subfamily ethylene response transcription factor domain, which is localized in the nucleus. Overexpression of GmERF071 enhanced SCN resistance in the soybean stable genetic transformation and root systems. RNA-seq analysis revealed 394 upregulated and 132 downregulated differentially expressed genes (DEGs) in GmERF071 overexpression transgenic plants. The DEGs participated in plant-pathogen interactions, mitogen-activated protein kinase signaling, plant hormone signal transduction, response to chitin, response to carbohydrates, response to wounding in starch and sucrose metabolism, phenylpropionic acid biosynthesis, and flavonoid biosynthesis. Nine candidate DEGs were verified using real-time quantitative reverse transcription PCR. These results suggest that GmERF071 plays a key role in SCN resistance and could be used in genomics-assisted breeding to develop soybean varieties with increased resistance to SCN.

Alpha lipoic acid modulates metabolic reprogramming in breast cancer stem cells enriched 3D spheroids by targeting phosphoinositide 3-kinase: In silico and in vitro insights

Breast cancer stem cells (BCSCs) are a unique subpopulation of tumor cells driving tumor resistance, progression, metastasis, and recurrence. Reprogrammed cellular metabolism and key signaling pathways, including Wnt/β-catenin, TGF-β, STAT3, and PI3K/AKT/mTOR pathway play a vital role in maintaining BCSCs. Importantly, PI3K/Akt/mTOR pathway regulates metabolism, survival, growth, and invasion, with PIK3CA, encoding the PI3K catalytic subunit p110α, the most frequently mutated gene in breast cancer. This study investigates the effects of alpha-lipoic acid (LA) on the metabolic profile of BCSCs, focusing on its interaction with PI3K signaling. LA was found to bind PI3K, disrupting cancer-associated metabolic pathways and significantly inhibiting BCSC metabolism. Metabolomic analysis of MCF-7 and MDA-MB-231-derived breast cancer spheroids showed LA-induced metabolic shifts. In MCF-7 spheroids, LA induced upaccumulation of 15 metabolites and downaccumulation of 5, while in MDA-MB-231 spheroids, it induced upaccumulation of 3 and downaccumulation of 16. LA also enhanced the sensitivity of breast cancer spheroids to doxorubicin (Dox), demonstrating a synergistic effect. Mechanistically, LA modulates the PI3K/Akt/mTOR pathway, impairing cell survival and proliferation. These findings highlight the potential of LA as a therapeutic agent for reprogramming cancer metabolism and enhancing chemotherapy efficacy. These results provide a strong rationale for incorporating LA into combination therapy strategies for breast cancer treatment.

Structure, Oligomerization, and Thermal Stability of a Recently Discovered Old Yellow Enzyme

The Old Yellow Enzyme from Ferrovum sp. JA12 (FOYE) displays an unusual thermal stability for an enzyme isolated from a mesophilic organism. We determined the crystal structure of this enzyme and performed bioinformatic characterization to get insights into its thermal stability. The enzyme displays a tetrameric quaternary structure; however, unlike the other tetrameric homologs, it clusters in a separate phylogenetic group and possesses unique interactions that stabilize this oligomeric state. The thermal stability of this enzyme is mainly due to an unusually high number of intramolecular hydrogen bonds. Finally, this study provides a general analysis of the forces driving the oligomerization in Old Yellow Enzymes.

In silico studies to understand the interactions of flavonoid inhibitor with nsp12-RNA dependent RNA polymerase of SARS-CoV-2 and its homologs

Aim

COVID 19 continues to be a major health concern. RNA dependent RNA polymerase of SARS-CoV-2 which is crucial for replication is therefore a potential drug target.

Methodology

Based on experimental structures of RdRp from SARS-CoV-2, computational models were generated of its homologs from SARS-C o V-1, MERS and Bat. SARS CoV-2 RdRp was used for virtual screening at nucleotide binding site with molecule from COCONUT Natural Products database using Glide. Complexes with the top inhibitor molecule were modelled using Discovery Studio and Desmond suite of programs.

Results

SARS-CoV-2 RdRp has a minimum of 80 % sequence similarity with its homologs, with the secondary structural elements, catalytic residues and metal binding residues being conserved. Certain residue variations in SARS-CoV-2 RdRp seems to be responsible for the stability of the enzyme. Docking and simulation studies showed that a flavonoid molecule with Coconut ID: CNP0127177.0 (HHF318) has binding affinity in low nano-molar range against RdRp from SARS-CoV-2 which was comparable or better than currently used inhibitors. This affinity stems from cationic-π with Arg555, and π-stacking interactions with a nucleobase of RNA. Molecule also engages with other residues that are crucial for its functions. This flavonoid molecule has similar physio-chemical properties like ATP towards SARS-CoV-2 RdRp, and has low potency for human ATP binding proteins.

Conclusion

HHF318 is a potential inhibitor of SARS-CoV-2 RdRp with good potency, specificity and pharmacokinetic properties for it to be developed as a drug candidate for COVID19.

Characterization of an iron-induced enzyme, nicotianamine synthase, from giant leucaena

Metal homeostasis in giant leucaena (Leucaena leucocephala subsp. glabrata) is of interest due to the plant's production of mimosine, an iron-chelating secondary metabolite. Real-time PCR performed on root and foliar tissue showed the upregulation of 19 genes following exogenous application of iron. Notable genes affected include glutathione synthase (20-fold increase in leaf), ferric chelate reductase (15-fold increase in root), mimosinase (20-fold increase in leaf) and nicotianamine synthase (30-fold increase in root). Transcriptome sequence data and 5'-RLM-RACE methods identified the complete nicotianamine synthase coding sequence, which was cloned for heterologous expression and in vitro assays. To properly assay nicotianamine synthase activity, due to strong feedback inhibition by 5'-methylthoadenosine, the giant leucaena 5'-methylthoadenosine nucleosidase was cloned and purified as well. Additional inhibition produced by the substrate compound, S-adenosylmethionine (SAM), was discovered in this study by utilizing a recombinant SAM-synthetase. Nicotianamine synthase is sensitive to racemic mixtures of SAM, which is inevitably produced in commercial SAM solutions. When substrate was produced in situ, using SAM-synthetase, nicotianamine synthase activity was 5-fold faster. Thus, in vitro nicotianamine synthase activity depends highly on two additional enzymes, the inclusion of MTA-nucleosidase being vital. Although promising, cell-free nicotianamine production methods are not yet efficient enough for industry-scale efforts. Sequence and structural analyses suggest residues involved in azetidine ring formation and other aspects of the mechanism are explored.

P21-Activated Kinase 1 (PAK1) Modulates Therapeutic Response to Ionizing Radiation in Head and Neck Squamous Cell Carcinoma Cells

Head and neck squamous cell carcinoma (HNSCC) continues to be a formidable epithelial malignancy characterized by late-stage detection and recurrence impacting survival. P21-activated kinase-1 (PAK1) was reported to be overexpressed in head and neck cancers and activated by ionizing radiation (IR), affecting treatment outcomes. Present investigations revealed that PAK1 silencing on HNSCC cells reverted the aggressive phenotype and showed impaired DNA damage repair upon IR exposure. Further HNSCC cells were resistant to IR up to 30 Gy with elevated pPAK1 levels. Radiation-resistant (RR) HNSCC cells expressed radiation-resistant markers, namely MRE-11 and NME-1; stemness markers-OCT4 and SOX2; and EMT & metastasis markers-vimentin, snail, and α-smooth muscle actin (α-SMA). In addition, HNSCC RR cells showed increased levels of DNA damage response protein H2AX, indicative of an aggressive phenotype with an augmented DNA repair machinery and a potential target for inhibition. Since H2AX appears to be a mechanistic hub for PAK1-induced radiation resistance, using in silico methods, peptides were designed, and the PL-8 peptide was chosen to target the phosphorylation of H2AX, which could enhance the sensitivity to IR and push the cells to radiation-induced cell death. PL-8 peptide inhibited H2AX phosphorylation on HNSCC cells and triggered radiation-induced cell death as determined by functional assays. The present study reveals PAK1 induced in HNSCC cells by IR and causes resistance by enhancing DNA damage response mediated through γH2AX. To counteract this complex molecular interplay, we propose inhibiting γH2AX formation & silencing PAK1 appears to be a probable way forward in HNSCC.

In-silico molecular investigation of Nannochloropsis microalgae cellulose synthase under salinity conditions and in-vitro evaluation of the proportionate effects on cellulose production

Nannochloropsis is a microalgae with more than substantially 60-70% cellulose in its cell wall, making it a potential candidate for nanocellulose sustainable production. This study examined the effects of salts in seawater and their role on Nannochloropsis gaditana and Nannochloropsis oculata cellulose synthase activity using In-silico and In-vitro approaches for the first time. Deep-learning-based AlphaFold2 predicted model was selected as the most reliable 3D structure. Molecular docking results revealed that none of the selected ligands occupied the binding site predicted for the native substrate of the enzyme, uridine-diphosphate. To validate the In-silico results, experiments were conducted to investigate the impact of salinity stress (NaCl, NaNO3 and NaHCO3) on the cell growth and cellulose production. The assessment tools included a UV-visible spectrophotometer and a hemocytometer, with a modified Jayme-Wise method used for cellulose extraction. The results indicated that the following concentrations of 0.443 mol/L, 0.457 mol/L, and 0.469 mol/L of NaCl, 0.072 mol/L, 0.077 mol/L, and 0.082 mol/L of NaNO3, 0.0021 mol/L, 0.0022 mol/L, and 0.0023 mol/L of NaHCO3 did not lower the growth rate nor the cellulose yield of N. oculata and notable enhancement in growth was observed in cultures supplemented with 0.0023 mol/L NaHCO3. Furthermore, when NaCl (0.457 mol/L and 0.469 mol/L), NaNO3 (0.082 mol/L) and NaHCO3 (0.0022 mol/L and 0.0023 mol/L) were individually introduced to the culture, cellulose yield increased up to five times compared to the control group.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04329-y.

NMR Structural Characterization of SARS-CoV-2 ORF6 Reveals an N-Terminal Membrane Anchor

SARS-CoV-2, the virus responsible for the COVID-19 pandemic, encodes several accessory proteins, among which ORF6, a potent interferon inhibitor, is recognized as one of the most cytotoxic. Here, we investigated the structure, oligomeric state, and membrane interactions of ORF6 using NMR spectroscopy and molecular dynamics simulations. Using chemical-shift-ROSETTA, we show that ORF6 in proteoliposomes adopts a straight α-helical structure with an extended, rigid N-terminal part and flexible C-terminal residues. Cross-linking experiments indicate that ORF6 forms oligomers within lipid bilayers, and paramagnetic spin labeling suggests an antiparallel arrangement in its multimers. The amphipathic ORF6 helix establishes multiple contacts with the membrane surface with its N-terminal residues acting as membrane anchors. Our work demonstrates that ORF6 is an integral monotopic membrane protein and provides key insights into its conformation and the importance of the N-terminal region for the interaction with the membrane.

mRNA vaccine design using the proteome of Theileria annulata through immunoinformatics approaches

Theileriosis exerts a substantial impact on ruminants, resulting in significant economic losses within the animal husbandry sector. The current vaccine, a live attenuated parasite, has several limitations that hinder effective disease control. This study utilized immunoinformatics to prioritize potential vaccine candidates and pointed to the design of a novel mRNA vaccine against Theileria annulata using in silico methods. Nine antigenic proteins were selected using various software, and their epitopes were identified through immunoinformatics tools. These epitopes were assessed for their biological traits and homology. Their presentation by major histocompatibility complex (MHC) cells and other immune cells was analyzed using molecular docking techniques. A multi-epitope protein was then modeled and optimized, followed by structural and stability analyses of the mRNA vaccine construct. Finally, the immune response to the new vaccine was simulated. The identified epitopes were localized within the antigen-binding sites of their respective MHC alleles. The newly formulated vaccine demonstrated stability, exhibited no toxicity, and showed non-allergenic characteristics. It effectively elicited responses from both the humoral and cellular immune systems. The findings suggest that the desired engineered mRNA vaccine paves the way for the development of the deterrence of theileriosis. This potential merits additional exploration through rigorous laboratory experiments and subsequent clinical trials.IMPORTANCEThis study presents a cutting-edge approach in vaccine design against bovine theileriosis, a devastating disease affecting cattle globally. By leveraging immunoinformatics methodologies, a novel mRNA vaccine candidate was tailored using computational analyzes of Theileria annulata proteins. Antigenic protein identification, epitope evaluation, and structural optimization of the multi-epitope mRNA vaccine are pivotal advancements in vaccine development. Using computational modeling tools to predict immune responses enhances the efficiency and accuracy of vaccine design, potentially revolutionizing preventive strategies against bovine theileriosis. This research not only demonstrates the potential of immunoinformatics in vaccine innovation but also sheds light on a promising avenue for combating a significant livestock health concern, offering hope for more effective and targeted veterinary interventions.

Unveiling the Modes of Action of a Recombinant Antimicrobial Peptide, Hepcidin (rGf-Hep), from Gerres filamentosus Against Pathogenic Vibrios: Membrane Disintegration and Reactive Oxygen Species Generation Leading to Cell Death

Antimicrobial peptides (AMPs) are essential components of the innate immune response, which play a significant role in combating pathogenic infections. Hepcidin, a peptide hormone predominantly synthesized in the liver, has been identified to exhibit dual functions in iron metabolism and antimicrobial activity across various organisms. In this study, we describe the molecular characteristics, anti-vibrio activity, and mechanisms of action of a novel hepcidin isoform from the commercially important estuarine fish, Whipfin silver-biddy (Gerres filamentosus). The open reading frame of hepcidin cDNA sequence was 273 base pairs in length, encoding a peptide of 90 amino acids. The active region Gf-Hep contains eight well-conserved cysteine residues which form disulfide bridges stabilizing the antiparallel beta sheet conformation of the peptide. Featuring a C-terminal furin cleavage site (RXXR) within the prodomain and an N-terminal 'QSHI/LS' motif in the mature region, Gf-Hep is classified with the HAMP1 group of fish hepcidins. Recombinantly expressed Gf-Hep exhibited robust antimicrobial activity against Vibrio parahaemolyticus, Vibrio fluvialis, Vibrio cholerae, and Vibrio alginolyticus. The modes of action of rGf-Hep included membrane depolarization, membrane permeabilization, and ROS production. With its potent antibacterial properties, direct killing mechanisms, and non-cytotoxic effects on normal cells, rGf-Hep holds promise to be developed as an effective anti-vibrio agent for aquaculture applications.

Integrative in silico and in vivo Drosophila model studies reveal the anti-inflammatory, antioxidant, and anticancer properties of red radish microgreen extract

Red radish microgreens (RRM) have gained considerable attention for their promising therapeutic potential. However, the molecular mechanisms underlying their bioactivity remain inadequately characterized. This study explores the anti-inflammatory, antioxidant, and anticancer properties of RRM extract using in silico and in vivo Drosophila model analyses. The metabolite profile of the RRM extract was characterized using comprehensive metabolomics techniques, including Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography High-Resolution Mass Spectrometry (LC-HRMS). Furthermore, in silico analysis utilizing network pharmacology identified target proteins of RRM compounds associated with cancer, inflammation, and oxidative stress. Concurrently, in vivo experiments with Drosophila melanogaster PGRP-LBΔ (Dm PGRP-LBΔ) larvae was conducted to assess the extract's impact on immune and oxidative stress pathways. In silico analysis revealed that RRM compounds interacted with key proteins (AKT1, ESR1, MAPK1, SRC, TP53), modulating pathways related to cancer, inflammation, and oxidative stress. Molecular dynamics simulations reinforced the docking results by confirming robust binding of kaempferitrin to AKT1. In vivo studies showed that RRM extract suppressed immune-related genes (dptA, totA) through the NFκB and JAK-STAT pathways, reduced ROS levels, and selectively regulated antioxidant gene expression by enhancing sod1 while decreasing sod2 and cat. These results suggest RRM extract as a functional food for managing oxidative stress, inflammation, and cancer. Further research in higher organisms and clinical settings is needed.

Comprehensive analysis of a novel LYST mutation in a Tunisian patient with Chediak-Higashi syndrome

BACKGROUND

Chediak-Higashi Syndrome (CHS) is a rare autosomal recessive disorder characterized by oculocutaneous albinism, recurrent infections, bleeding tendencies, and progressive neurological impairment. The syndrome is caused by mutations in the LYST gene, which plays a crucial role in lysosomal trafficking.

OBJECTIVE

This study aims to characterize the molecular basis of CHS in a Tunisian patient by identifying mutations in the LYST gene and analyzing their impact on the protein function, correlating these findings with the patient's clinical presentation.

METHODS

A comprehensive clinical assessment was conducted on the patient, followed by biochemical, hematological, and microbiological analyses. Additionally, LYST protein levels were quantified in the patient and their parents using an ELISA assay. Genomic DNA was extracted from the patient's blood, and Whole Exome Sequencing (WES) was performed to identify mutations in the LYST gene. The findings were confirmed through Sanger sequencing, and bioinformatic tools were employed to predict the functional consequences of the detected mutations.

RESULTS

The patient presented with classical symptoms of CHS, including silver hair, hypopigmented skin, recurrent infections, and neurological decline, with an unusually late onset at 18 years. ELISA results demonstrated significantly reduced LYST levels in the patient (1.8 ng/ml) compared to heterozygous parents (7.8 ng/ml and 8.1 ng/ml) and controls (9.2 ng/ml). Genetic analysis revealed a novel homozygous deletion, c.10269_10275del (p.Gly3424SerfsTer15), in the LYST gene, leading to a frameshift mutation and premature termination of the protein. Bioinformatic analysis demonstrated that this mutation leads to the deletion of five out of sven WD40 repeats in the protein's C-terminal region, which are critical for protein-protein interactions and lysosomal trafficking.

CONCLUSION

The study identifies a novel LYST mutation in a Tunisian patient with CHS, expanding the spectrum of known genetic variants associated with the disease. The findings highlight the importance of genetic screening in populations with high consanguinity and underscore the need for targeted therapies to address the molecular defects in CHS.

Binding of transmissible gastroenteritis virus and porcine respiratory coronavirus to human and porcine aminopeptidase N receptors as an indicator of cross-species transmission

Coronaviruses have the ability to overcome interspecies barriers and adapt to new hosts, posing significant epidemic risks in cases of zoonotic transmission to humans. A critical factor in this process is the interaction between coronavirus spike proteins and host cell surface receptors, which plays an important role in infection and disease progression. This study focused on two representatives of coronaviruses: transmissible gastroenteritis virus (TGEV) and its mutant, porcine respiratory coronavirus (PRCV), both of which naturally cause disease in pigs. A phylogenetic analysis of previously identified strains of these viruses was performed, and the conservation of receptor-binding domain (RBD) sequences within their spike proteins was evaluated. In silico modeling was performed for complexes of the RBDs from 16 virus strains with porcine aminopeptidase N (APN), as well as for putative complexes with the human APN receptor. The binding free energy of these modeled complexes was evaluated, along with the impact of more than 500 theoretical mutations in the RBD. The computational results suggest that the TGEV 133 strain exhibits the highest affinity for both porcine and human receptors, with only two additional mutations required to further enhance this affinity. Molecular dynamics simulations were conducted for porcine and human APN complexes with known TGEV strains (Purdue and 133) as well as a theoretical mutated strain. These simulations reveal differences in the dynamic behavior of complexes with porcine and human receptors and support the hypothesis that mutagenesis at a few key amino acid residues in the RBD could enable TGEV to achieve affinity for human APN comparable to that of its natural host receptor. The findings underscore a theoretical risk of zoonotic transmission of these coronaviruses to humans, emphasizing the importance of further monitoring these pathogens.