Search Results (824)

Alpha2-plasmin inhibitor (α2PI) has a heterogeneous structure due to proteolytic cleavages in the circulation. The C-terminally cleaved form loses the plasminogen binding site and is, therefore, a slow plasmin inhibitor (NPB-α2PI). As FXIII primarily crosslinks the plasminogen-binding intact form (PB-α2PI) to fibrin, the effect of NPB-α2PI on fibrinolysis has been less studied. Herein, we investigated the effect of C-terminal truncation. Total-, PB-, and NPB-α2PI antigen levels and α2PI incorporation were measured by ELISAs from samples of 80 healthy individuals. Clot lysis parameters of the same subjects were investigated using an in vitro clot lysis assay. α2PI incorporation into the clot was demonstrated by Western blotting. Clot lysis and clot structure were also analyzed using an α2PI-deficient plasma substituted with recombinant PB- and NPB-α2PI. Both plasma and clot-bound levels of total- and NPB-α2PI showed a significant positive correlation with clot lysis parameters. NPB-α2PI was detected in the clot due to non-covalent binding. Regardless of the type of binding, both forms affected the clot structure by increasing the thickness of the fibrin fibers and reducing the pore size. In conclusion, we found that NPB-α2PI can bind non-covalently to fibrin, and this binding contributes to changes in clot structure and inhibition of fibrinolysis. Full article

Fungal lytic polysaccharide monooxygenases (LPMOs) have revolutionized the field of biomass degradation by introducing an oxidative mechanism that complements traditional hydrolytic enzymes. These copper-dependent enzymes catalyze the cleavage of glycosidic bonds in recalcitrant polysaccharides such as cellulose, hemicellulose, and chitin, through the activation of molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). Their catalytic versatility is intricately modulated by structural features, including the histidine brace active site, surface-binding loops, and, in some cases, appended carbohydrate-binding modules (CBMs). The oxidation pattern, whether at the C1, C4, or both positions, is dictated by subtle variations in loop architecture, amino acid microenvironments, and substrate interactions. LPMOs are embedded in a highly synergistic fungal enzymatic system, working alongside cellulases, hemicellulases, lignin-modifying enzymes, and oxidoreductases to enable efficient lignocellulose decomposition. Industrial applications of fungal LPMOs are rapidly expanding, with key roles in second-generation biofuels, biorefineries, textile processing, food and feed industries, and the development of sustainable biomaterials. Recent advances in genome mining, protein engineering, and heterologous expression are accelerating the discovery of novel LPMOs with improved functionalities. Understanding the balance between O₂- and H₂O₂-driven mechanisms remains critical for optimizing their catalytic efficiency while mitigating oxidative inactivation. As the demand for sustainable biotechnological solutions grows, this narrative review highlights how fungal LPMOs function as indispensable biocatalysts for the future of the Circular Bioeconomy and green industrial processes. Full article

Inherited epidermolysis bullosa (EB) is a heterogeneous clinical entity that includes over 30 phenotypically and/or genotypically distinct inherited disorders, characterized by mechanical skin fragility and bullae formation. Junctional EB (JEB) is an autosomal recessive disease characterized by an intermediated cleavage level within the skin layers, commonly at the “lamina lucida”. Laryngo-onycho-cutaneous syndrome (LOC) is an extremely rare variant of JEB, characterized by granulation tissue formation in specific body sites (skin, larynx, and nails). Although most cases of JEB are caused by pathogenic variants occurring in the genes encoding for classical components of the lamina lucida, such as laminin 332 (LAMA3, LAMB3, LAMC2), integrin α6β4 (ITGA6, ITGB4), and collagen XVII (COL17A1), other variants have also been described. We report the case of a 4-month-old male infant who presented with recurrent bullous and erosive lesions from the first month of life. At the first dermatological evaluation, the patient was agitated and exhibited hoarse breathing, a clinical sign suggestive of laryngeal involvement. Multiple polygonal skin erosions were observed on the cheeks, along with similar isolated, roundish lesions on the scalp and legs. Notably, nail dystrophy and near-complete anonychia were evident on the left first and fifth toes. Due to the coexistence of skin erosions and nail dystrophy in such a young infant, a congenital bullous disorder was suspected, prompting molecular analysis of all potentially involved genes. In the patient’s DNA, clinical exome sequencing (CES) identified a pathogenic variant, apparently in homozygosity, in the exon 1 of the LAMA3 gene (18q11.2; NM_000227.6): c.47G > A;p.Trp16*. The presence of this variant was confirmed, in heterozygosity, in the genomic DNA of the patient’s mother, while it was absent in the father’s DNA. Subsequently, trio-based SNP array analysis was performed, revealing a paternally derived pathogenic microdeletion encompassing the LAMA3 locus (18q11.2). To our knowledge, this is the first reported case of JEB with a LOC-like phenotype caused by a maternally inherited monoallelic nonsense mutation in LAMA3, unmasked by an almost complete deletion of the paternal allele. The combined use of exome sequencing and SNP array is proving essential for elucidating autosomal recessive diseases with a discordant segregation. This is pivotal for providing accurate genetic counseling to parents regarding future pregnancies. Full article

γ-Glutamyl transpeptidase (GGT) is overexpressed in a variety of diseases, making it an important diagnostic criterion for diseases. Herein, a new fluorescence probe based on naphthalimide (Glu-MDA) was developed and employed for the rapid detection of GGT in tumor cells or samples. Alkynylated naphthalimide is the fluorescent core for excellent fluorescence response. The covalent bridging of self-immolative short linkers reduces the steric hindrance between probes and enzyme cleavage sites, which leads to improved enzymatic reaction kinetics. Glu-MDA shows a rapid response and excellent selectivity with a detection limit of 0.044 U/L. This allows the efficient detection of GGT levels in solution and cells. Simultaneously, the construction of Glu-MDA pre-stained test strips provided an innovative strategy for the qualitative detection of GGT activity, helping to detect GGT faster, more portably, and cost-effectively in various scenarios. Full article

Pest management is undergoing a transformative shift with the development of the cutting-edge antisense technologies: RNA interference (RNAi), contact unmodified antisense DNA biotechnology (CUADb), and the CRISPR-associated proteins (CRISPR/Cas). These approaches function by facilitating sequence-specific pairing of nucleic acids followed by nuclease-mediated cleavage, offering exceptional precision for targeted pest control. While RNA-guided mechanisms such as RNAi and CRISPR/Cas were initially characterized in non-insect systems, primarily as innate defenses against viral infections, the DNA-guided CUADb pathway was first identified in insect pests as a functional pest control strategy. Its broader role in ribosomal RNA (rRNA) biogenesis was recognized later. Together, these discoveries have revealed an entirely new dimension of gene regulation, with profound implications for sustainable pest management. Despite sharing a common principle of sequence-specific targeting RNAi, CUADb, and CRISPR/Cas differ in several key aspects, including their mechanisms of action, target specificity, and applicability. Rather than serving as universal solutions, each technology is likely to be optimally effective against specific pest groups. Moreover, these technologies allow for rapid adaptation of control strategies to overcome target-site resistance, ensuring long-term efficacy. This review summarizes the core functional characteristics, potential applications, and current limitations of each antisense technology, emphasizing their complementary roles in advancing environmentally sustainable pest control. By integrating foundational biological discoveries with applied innovations, this work provides a new perspectives on incorporating antisense-based strategies into next-generation integrated pest management systems. Full article

Background/Objectives: PEGylated liposomes are widely recognized for their biocompatibility and capacity to extend systemic circulation via “stealth” properties. However, the PEG corona often limits tumor penetration and cellular internalization. Targeting matrix metalloproteinase-2 (MMP-2), frequently upregulated in breast cancer stroma, presents an opportunity to enhance tissue-specific drug delivery. In this study, we engineered MMP-2-responsive GPLGVRG peptide-modified cleavable PEGylated liposomes for targeted paclitaxel (PTX) delivery. Methods: Molecular docking simulations employed the MMP-2 crystal structure (PDB ID: 7XJO) to assess GPLGVRG peptide binding affinity. A cleavable, enzyme-sensitive peptide-PEG conjugate (Chol-PEG_2K-GPLGVRG-PEG_5K) was synthesized via small-molecule liquid-phase synthesis and characterized by ¹H NMR and MALDI-TOF MS. Liposomes incorporating this conjugate (S-Peps-PEG_5K) were formulated to evaluate whether MMP-2-mediated peptide degradation triggers detachment of long-chain PEG moieties, thereby enhancing internalization by 4T1 breast cancer cells. Additionally, the effects of tumor microenvironmental pH (~6.5) and MMP-2 concentration on drug release dynamics were investigated. Results: Molecular docking revealed robust GPLGVRG-MMP-2 interactions, yielding a binding energy of −7.1 kcal/mol. The peptide formed hydrogen bonds with MMP-2 residues Tyr A:23 and Arg A:53 (bond lengths: 2.4–2.5 Å) and engaged in hydrophobic contacts, confirming MMP-2 as the primary recognition site. Formulations containing 5 mol% Chol-PEG_2K-GPLGVRG-PEG_5K combined with 0.15 µg/mL MMP-2 (S-Peps-PEG_5K +MMP) exhibited superior internalization efficiency and significantly reduced clonogenic survival compared to controls. Notably, acidic pH (~6.5) induced MMP-2-mediated cleavage of the GPLGVRG peptide, accelerating S-Peps-PEG_5K dissociation and facilitating drug release. Conclusions: MMP-2-responsive, cleavable PEGylated liposomes markedly improve PTX accumulation and controlled release at tumor sites by dynamically modulating their stealth properties, offering a promising strategy to enhance chemotherapy efficacy in breast cancer. Full article

Angiotensin-converting enzyme 2 (ACE2) is a cell-surface receptor that helps the body regulate blood pressure and endocrine secretions. Transmembrane serine protease 2 (TMPRSS2) is a cell surface protein expressed mainly by endothelial cells of the respiratory and digestive tract, which participates in the cleavage of protein peptide bonds with serine as the active site. These two proteins have been studied to be highly associated with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Soybean trypsin inhibitor (SBTI) has special bioactivities such as anticarcinogenic and anti-inflammatory functions, which can be widely used in functional foods or drugs. Our study involved in vitro and in vivo experiments to elucidate the effect of SBTI on SARS-CoV-2 host invasion. First, it was confirmed that being under 250 μg/mL of SBTI was not toxic to HepG2, HEK293T, and Calu-3 cells. The animal study administered SBTI to mice once daily for 14 days. In the lungs, liver, and kidneys, the histopathologic findings of the SBTI group were not different from those of the control group, but the expression of ACE2, TMPRSS2, and CD147 was reduced. Thus, our findings suggest that the inhibition of ACE2, TMPRSS,2 and CD147 proteins by SBTI shows promise in potentially inhibiting SARS-CoV-2 infection. Full article

A restriction enzyme PsaI, an isoschizomer of the type II restriction endonuclease HindIII, has been purified to homogeneity from Gram-negative bacilli Pseudomonas anguilliseptica KM9 found in a wastewater treatment plant in Poland. Experimental data revealed that R.PsaI is highly active in the presence of Co²⁺, Mg²⁺, and Zn²⁺ and reached a maximal level of activity between 2.5 and 10 mM while its activity was significantly decreased in the presence of Ca²⁺, Fe²⁺, Mn²⁺, and Ni²⁺. Moreover, we found that the purified R.PsaI did not require NaCl for enzyme activity. Restriction cleavage analysis followed by sequencing confirmed 5′-AAGCTT-3′ as the recognition site. The genes for restriction–modification system PsaI were identified and characterized. Downstream of the psaIM gene, we noticed an ORF that shares extensive similarity with recombinase family protein specifically involved in genome rearrangements. Sequence analysis revealed that the PsaI R-M gene complex showed striking nucleotide sequence similarity (>98%) with the genes of the PanI R-M system from a P. anguilliseptica MatS1 strain identified in a soil sample from Sri Lanka. Full article

The new mineral achyrophanite (K,Na)₃(Fe³⁺,Ti,Al,Mg)₅O₂(AsO₄)₅ was found in high-temperature sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with aphthitalite-group sulfates, hematite, alluaudite-group arsenates (badalovite, calciojohillerite, johillerite, nickenichite, hatertite, and khrenovite), ozerovaite, pansnerite, arsenatrotitanite, yurmarinite, svabite, tilasite, katiarsite, yurgensonite, As-bearing sanidine, anhydrite, rutile, cassiterite, and pseudobrookite. Achyrophanite occurs as long-prismatic to acicular or, rarer, tabular crystals up to 0.02 × 0.2 × 1.5 mm, which form parallel, radiating, bush-like, or chaotic aggregates up to 3 mm across. It is transparent, straw-yellow to golden yellow, with strong vitreous luster. The mineral is brittle, with (001) perfect cleavage. D_calc is 3.814 g cm^–3. Achyrophanite is optically biaxial (+), α = 1.823(7), β = 1.840(7), γ = 1.895(7) (589 nm), 2V (meas.) = 60(10)°. Chemical composition (wt.%, electron microprobe) is: Na₂O 3.68, K₂O 9.32, CaO 0.38, MgO 1.37, MnO 0.08, CuO 0.82, ZnO 0.48, Al₂O₃ 2.09, Fe₂O₃ 20.42, SiO₂ 0.12, TiO₂ 7.35, P₂O₅ 0.14, V₂O₅ 0.33, As₂O₅ 51.88, SO₃ 1.04, and total 99.40. The empirical formula calculated based on 22 O apfu is Na_1.29K_2.15Ca_0.07Mg_0.34Mn_0.01Cu_0.11Zn_0.06Al_0.44Fe³⁺_2.77Ti_1.00Si_0.02P_0.02S_0.14V_0.04As_4.90O₂₂. Achyrophanite is orthorhombic, space group P222₁, a = 6.5824(2), b = 13.2488(4), c = 10.7613(3) Å, V = 938.48(5) ų and Z = 2. The strongest reflections of the PXRD pattern [d,Å(I)(hkl)] are 5.615(59)(101), 4.174(42)(022), 3.669(31)(130), 3.148(33)(103), 2.852(43)(141), 2.814(100)(042, 202), 2.689(29)(004), and 2.237(28)(152). The crystal structure of achyrophanite (solved from single-crystal XRD data, R = 4.47%) is unique. It is based on the octahedral-tetrahedral M-T-O pseudo-framework (M = Fe³⁺ with admixed Ti, Al, Mg, Na; T = As⁵⁺). Large-cation A sites (A = K, Na) are located in the channels of the pseudo-framework. The achyrophanite structure can be described as stuffed, with the defect heteropolyhedral pseudo-framework derivative of the orthorhombic Fe³⁺AsO₄ archetype. The mineral is named from the Greek άχυρον, straw, and φαίνομαι, to appear, in allusion to its typical straw-yellow color and long prismatic habit of crystals. Full article

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease of 2019 (COVID-19) and has persistently caused infections since its emergence in late 2019. The main protease (Mpro) of SARS-CoV-2 plays a crucial role in its life-cycle; thus, it is an important target for drug development. One of the first virus-specific drugs that has been approved for the treatment of COVID-19 patients is Paxlovid, which contains nirmatrelvir, a covalent inhibitor of Mpro. Screening of inhibitor candidates and specificity studies also rely on efficient substrates and activity assays. Casein is one of the most commonly applied universal substrates that can be used to study a wide range of proteases, including SARS-CoV-2 Mpro. Casein is a known substrate for Mpro in vitro, but the specific casein isoform cleaved by Mpro remained unidentified, and the cleavage sites have yet to be determined. This work studied cleavage of α-, β- and κ-isoforms of bovine casein by SARS-CoV-2 Mpro, using in vitro and in silico approaches. The candidate cleavage sites were predicted in silico based on the protein sequences, and the cleavage positions were identified based on mass spectrometric analysis of cleavage fragments. Based on our results, only β-casein contains cleavage sites for Mpro and thus can be used as its substrate in vitro. The newly identified cleavage site sequences further widen the knowledge about the specificity of SARS-CoV-2 Mpro. Full article

Finding alternatives to platinum that exhibit high activity, stability, and abundant reserves as oxygen reduction electrocatalysts is crucial for the advancement of fuel cells. In this study, we first mixed FeCl₂·4H₂O, 1,10-phenanthroline, and Vulcan XC-72, followed by pyrolysis in a nitrogen atmosphere, to obtain FeNC. Subsequently, we combined FeNC with MXene produce FeNC/MXene composites. The FeNC/MXene catalyst achieved a half-wave potential of 0.857 V in an alkaline medium, exhibiting better oxygen reduction reaction (ORR) activity and durability than commercial Pt/C catalysts. The layered structure of MXene endows the material with a high specific surface area and facilitates efficient electron transfer pathways, thereby promoting rapid charge transfer and material diffusion. The cleavage of Ti-C bonds in Ti₃C₂ at elevated temperatures results in the transformation of MXene into TiO₂, where the coexistence of anatase and rutile phases generates a synergistic effect that enhances both the mass transfer rate and the electrical conductivity of the catalytic layer. Additionally, the unique electronic structure of the FeN_x sites simultaneously optimizes electrocatalytic activity and stability. Leveraging these structural advantages, the FeNC/MXene composite catalysts demonstrate exceptional catalytic activity and long-term stability in oxygen reduction reactions. Full article

Cyclohexane-containing semi-aromatic polyamides (c-SaPA) exhibit excellent comprehensive properties. Existing studies predominantly focus on synthesis and modification, while fundamental investigations into pyrolysis mechanisms remain limited, which restricts the development of advanced materials for high-performance applications such as automotive and energy systems. This study employs Reactive Force Field Molecular Dynamics (ReaxFF-MD) simulations to establish a pyrolysis model for poly(terephthaloyl-hexahydro-m-xylylenediamine) (PHXDT), systematically probing its pyrolysis kinetics and evolutionary pathways under elevated temperatures. The simulation results reveal an activation energy of 107.55 kJ/mol and a pre-exponential factor of 9.64 × 10¹³ s⁻¹ for the pyrolysis process. The primary decomposition pathway involves three distinct stages. The first is initial backbone scission generating macromolecular fragments, followed by secondary fragmentation that preferentially occurs at short-chain hydrocarbon formation sites alongside radical recombination. Ultimately, the process progresses to deep dehydrogenation, carbonization, and heteroatom elimination through sequential reaction steps. Mechanistic analysis identifies multi-pathway pyrolysis involving carboxyl/amide bond cleavage and radical-mediated transformations (N-C-O, C-C-O, OH· and H·), yielding primary products including H₂, CO, H₂O, CH₃N, C₂H₂, and C₂H₄. Crucially, the cyclohexane structure demonstrates preferential participation in dehydrogenation and hydrogen transfer reactions due to its conformational dynamic instability and low bond dissociation energy, significantly accelerating the rapid generation of small molecules like H₂. Full article

This study presents the development and validation of an elementary reaction pathway tracking algorithm based on reactive force field simulations, enabling the dynamic monitoring of cracking products at the 20,000-atom scale, the accurate identification of chain reaction pathways, and the comprehensive tracking of large carbon chain formation. The research demonstrates that the differences between methane and propylene cracking–polymerization reactions primarily stem from disparities in bond dissociation energies, radical stabilities, and molecular topologies, and the operation of molecular dynamics relies on LAMMPS 3 March 2020. The cracking pathway of methane is relatively straightforward, predominantly involving the homolytic cleavage of C–H bonds, followed by radical chain propagation leading to the formation of large carbonaceous species. In contrast, propylene, owing to its unsaturated structure and multiple reactive sites, exhibits more complex reaction networks and a wider diversity of products. Furthermore, the study elucidates the reaction pathways of intermediate species during methane and propylene cracking and investigates the effect of reaction temperature on carbon sheet development. In conclusion, the algorithm established in this work offers a detailed mechanistic insight into the gas-phase cracking of methane and propylene, providing a new theoretical basis for the optimization of gas-phase deposition processes and the rational design of carbon-based materials. Full article

Monomer-to-excimer transition has become a valuable technique in fluorescence imaging because of its ability to enhance imaging contrast. However, from a practical perspective, the accuracy of excimer formation at target sites warrants further exploration. Enzyme-triggered peptide self-assembly provides a promising solution to this limitation. As a proof-of-concept, in this study, we developed a furin-triggered peptide self-assembling fluorescent probe RF-Cou by coupling a coumarin dye 7-(diethylamino)-2-oxo-2H-chromene-3-carboxylic acid (Cou) with a furin-responsive peptide scaffold for precision live-cell imaging. Upon entering furin-overexpressing 4T1 tumor cells, RF-Cou underwent enzymatic cleavage, releasing an amphiphilic peptide motif and self-assembling into nanoparticles largely concentrated in the Golgi apparatus to confine the diffusion of Cou. During this process, the Cou excimers were formed and induced a red shift in the fluorescence emission, validating the feasibility of RF-Cou in efficient excimer imaging of furin-overexpressing tumor cells. We expect that our findings will highlight the potential of stimuli-responsive small molecular peptide probes to advance excimer-based imaging platforms, particularly for enzyme-specific cell imaging and therapeutic monitoring. Full article

The proteolytic processing of the SARS-CoV-2 spike glycoprotein by host cell membrane-associated proteases is a key step in both the entry of the invading virus into the cell and the release of the newly generated viral particles from the infected cell. Because of the critical importance of this step for the viral infectivity cycle, it has been a target of extensive efforts aimed at identifying highly specific protease inhibitors as potential antiviral agents. An alternative strategy to disrupt the pre-fusioviden processing of the SARS-CoV-2 S glycoprotein aims to protect the substrate rather than directly inhibit the proteases. In this work, we focused on furin, a serine protease located primarily in the Golgi apparatus, but also present on the cell membrane. Its cleavage site within the S glycoprotein is located within the stalk region of the latter and comprises an arginine-rich segment (SPRRARS), which fits the definition of the Cardin–Weintraub glycosaminoglycan recognition motif. Native mass spectrometry (MS) measurements confirmed the binding of a hexadecameric peptide representing the loop region at the S1/S2 interface and incorporating the furin cleavage site (FCS) to heparin fragments of various lengths, as well as unfractionated heparin (UFH), although at the physiological ionic strength, only UFH remains tightly bound to the FCS. The direct LC/MS monitoring of FCS digestion with furin revealed a significant impact of both heparin fragments and UFH on the proteolysis kinetics, although only the latter had IC50 values that could be considered physiologically relevant (0.6 ± 0.1 mg/mL). The results of this work highlight the importance of the long-range and relatively non-specific electrostatic interactions in modulating physiological and pathological processes and emphasize the multi-faceted role played by heparin in managing coronavirus infections. Full article