Search Results (902)

The islet amyloid polypeptide (IAPP) is a peptide hormone playing key biological roles, including glucose homeostasis and regulation of food intake, conferring high therapeutic potential to treat metabolic disorders. Nonetheless, IAPP is mainly known as the major component of the amyloid fibrils observed in the pancreatic islets of patients afflicted with type 2 diabetes, and the accumulation of these insoluble protein deposits correlates closely with the loss of pancreatic β-cells. The inherent aggregation propensity of this peptide hormone is not only associated with the pathogenesis of type 2 diabetes but also complicates the design of IAPP derivatives for the treatment of metabolic disorders. Accordingly, elucidating the molecular mechanisms by which IAPP self-assembles into amyloid fibrils is critical to identify chemical strategies to arrest aggregation, as well as to design safe and stable IAPP-derived therapeutics. This review aims at presenting the different mechanistic models of IAPP aggregation and how to exploit this information to identify inhibitors of amyloid formation and non-aggregating peptide agonists. After discussing the conformational conversions allowing IAPP to undergo a mainly disordered monomeric conformation into ordered cross-β-sheet quaternary supramolecular structures, we present chemical strategies to prevent amyloid deposition and to develop non-aggregating peptide-based therapeutics. Full article

To investigate the effect of phenolic hydroxyl group number on the interaction between catechins and a plant-derived protein carrier, four catechins with varying hydroxyl numbers—epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG)—were investigated. The new plant-derived edible dock protein (EDP) was selected as a carrier matrix. EDP, when employed as a protein delivery carrier, possessed a hydrophobic amino acid content of 45%. This structural feature enabled it to provide more hydrophobic cavities for small molecule compounds, thereby facilitating better binding with them. The results indicated that the order of loading capacity of catechins within EDP was EGCG (9.7%) > ECG (9.1%) > EGC (8.8%) > EC (7.1%). This sequence was consistent with the number of hydroxyl groups in catechin: EGCG (8) > ECG (7) > EGC (6) > EC (5). Among the four catechins, EGCG had the highest binding constant (Ka = 2.6 × 10³ L/mol), leading to the largest quenching of EDP. During self-assembly, hydrogen bonding, hydrophobic and electrostatic interactions were the main driving forces, and the interaction between EGCG and EDP was the strongest. This study indicated that the hydroxyl group number of polyphenolic compounds can determine its binding affinity with proteins. Full article

Surface fouling remains a critical challenge for medical devices and chemosensor systems operating in biological environments, where nonspecific adsorption of proteins, cells, and microorganisms can lead to signal drift, reduced sensitivity, and shortened device lifetime. Conventional antifouling strategies rely primarily on synthetic hydrophilic polymer coatings, such as polyethylene glycol and polyvinylpyrrolidone, which are effective but face limitations related to long-term stability, thickness, and compatibility with surface-sensitive sensing modalities. In this review, we focus on hydrophobins derived from mushroom-forming and filamentous fungi as a bio-based alternative for antifouling and anti-wetting surface modification. Mushroom-derived hydrophobins are small amphiphilic proteins capable of spontaneous self-assembly into nanometer-scale films that modulate surface energy, wettability, and interfacial friction without requiring covalent functionalization. The current state of research on hydrophobin structure, classification, and self-assembly is reviewed, followed by a synthesis of reported antifouling and tribological behaviors relevant to medical and sensor-adjacent surfaces. Representative experimental observations are discussed to illustrate trends consistent with the literature, without establishing new performance benchmarks. The implications of mushroom-derived hydrophobin coatings for chemosensors and biosensors are examined, particularly with respect to signal stability, surface accessibility, and durability. Limitations and future research directions are outlined to support translation into practical sensing technologies. Full article

Protein-based nanocarriers have gained considerable attention for targeted cancer theranostic applications due to their inherent biocompatibility, biodegradability, and facile functionalisation. In addition, some of their properties, such as self-assembling nature, low immunogenicity (if species matched), molecular recognition ability, and lack of persistence due to degradation into proteinogenic amino acids, make them highly suitable for oncology-related applications. Each protein-based nanocarrier exhibits unique physicochemical and biological properties. In this review, we summarise recent advances in targeted protein-based nanocarriers, including albumin, lipoproteins, ferritin, viral protein capsids, fibrin type proteins and silk proteins, emphasising receptor-specific targeting mechanisms, the integration of various imaging modalities along with their advantages and limitations, and the importance of employing advanced preclinical models for translational theranostic applications. This review also discusses the most recent and significant studies in the field, providing useful insights into future directions of protein-based nanocarriers for cancer theranostics. Full article

α-Synuclein (α-syn) aggregation underlies synucleinopathies, yet the physicochemical determinants that govern which assembly states form under defined solution conditions remain incompletely resolved. Here, we examine how pH and metal ions reshape α-syn self-assembly. Across acidic and physiological pH conditions, α-syn populates monomeric, nanoscale oligomeric, and mesoscale aggregate states whose relative abundances evolve over time. Fluorescence microscopy reveals robust mesoscale assembly at pH 5, minimal aggregation at pH 7, and transient assemblies at pH 3, highlighting the limitations of imaging-based detection alone. Therefore, we use dynamic light scattering (DLS) to resolve oligomeric populations and quantify pH-dependent redistribution of assembly mass. Toxicity-mitigating modulators altered α-syn assembly in a strongly pH-dependent manner. Anle138b increased the abundance of oligomeric species at low pH, whereas EGCG produced divergent effects at pH 5 and pH 3. We further examined the effects of metal ions, finding that Fe³⁺ stabilized higher-order assemblies under acidic conditions, Cu²⁺ delayed assembly at pH 5 while enhancing aggregation at pH 3, and Zn²⁺ increased oligomerization primarily at low pH. Overall, these results demonstrate that α-syn assembly is highly sensitive to coupled effects of pH, metal chemistry, and time. Full article

The persistent emergence of infectious diseases has underscored the critical demand for next-generation vaccine technologies that are safe, effective, and scalable. This review explores virus biomimetic delivery systems, focusing on virus-like particles (VLPs) and virosomes as promising platforms for vaccine and therapeutic development. VLPs are self-assembled nanostructures composed of viral structural proteins that mimic native virions without carrying genetic material, while virosomes are reconstituted viral envelopes that retain functional glycoproteins but lack a nucleocapsid. Both systems provide strong immunogenicity and safety by mimicking viral architecture while eliminating the risk of replication. The paper examines various expression platforms for VLP production, including bacterial, yeast, insect, mammalian, and plant-based systems, highlighting their respective advantages, challenges, and optimization strategies. Mechanistic insights into antigen presentation, immune activation, and cellular uptake pathways are discussed to explain their superior performance in eliciting humoral and cellular immune responses. Furthermore, current applications of VLPs and virosomes in vaccines against major pathogens such as SARS-CoV-2, influenza, Newcastle disease virus, malaria, hepatitis, and respiratory syncytial virus are reviewed, demonstrating their versatility and clinical potential. By integrating molecular engineering, nanotechnology, and biofabrication strategies, virus biomimetic systems represent a transformative frontier in vaccinology, immunotherapy, and targeted drug delivery. Full article

Staphylococcus aureus, particularly its multidrug-resistant strains, poses a critical biological hazard throughout the global food supply chain, underscoring the need to transition from inert petroleum-based packaging to active, biodegradable alternatives. This review presents a comprehensive analysis of the structure function relationships and interfacial interaction mechanisms that govern polysaccharide-, protein-, and lipid-based films designed for the targeted inhibition of S. aureus. We critically evaluate the extent to which the intrinsic molecular features—such as the polycationic charge density of chitosan and the amphiphilic self-assembly of fatty acids—determine baseline antibacterial activity. A key contribution of this work is the elucidation of three synergistic pathways: physical barrier effects, chemical interference, and biological regulation. Furthermore, we discuss how composite systems, such as polysaccharide lipid hybrids and protein nanomaterial scaffolds, exploit charge complementarity and controlled-release kinetics to surpass the performance limitations of single-component materials. Finally, we address the critical trade-offs between mechanical integrity and antimicrobial efficacy, proposing a roadmap for intelligent, stimuli-responsive packaging that is capable of responding to microbial metabolic cues. Overall, this review provides a theoretical foundation for the rational design of high-performance biodegradable films to safeguard global food safety. Full article

Protein phosphorylation and dephosphorylation reactions of intracellular molecules catalyzed by enzymes such as kinases and phosphatases are essential reactions in a lot of cellular functions such as intracellular signal transduction in living systems. The design and synthesis of artificial enzyme mimics are important research topics in bioorganic and bioinorganic chemistry. In this paper, we report on the construction of artificial phosphatases via the supramolecular self-assembly of compounds such as an amphiphilic bis(Zn²⁺-cyclen) (cyclen = 1,4,7,10-tetraazacyclododecane) complex, barbital derivatives modified with benzocrown ethers and boronophenyl groups, and a copper(II) ion in a two-phase solvent system. We have developed a hypothesis whereby a mono(4-nitrophenyl)phosphate (MNP) substrate coordinates to the Cu₂(µ-OH)₂ core in supramolecular complexes and is activated either by Lewis acidic units such as alkali metal (Li⁺, Na⁺ and K⁺)-benzocrown ether complexes or by boronophenyl moieties. The findings suggest that supramolecular phosphatase functionalized with a benzo-12-crown-4-Li⁺ complex shows a higher level of activity in the MNP hydrolysis of a two-phase solvent system compared with that of our previous supramolecular phosphatases in terms of hydrolysis activity and catalytic turnover. Full article

Background/Objectives: Aberrant metabolism in tumors exacerbates the immunosuppressive tumor microenvironment. The immunosuppressive metabolite kynurenine inhibits the activation of effector T cells. Current antitumor drugs targeting kynurenine focus on small molecule inhibitors, which exhibit suboptimal efficacy in suppressing kynurenine generation owing to the diversity of kynurenine synthesis pathways. In contrast, kynureninase (KYNase) can directly metabolize kynurenine regardless of the production source. However, its delivery is hindered by short blood-circulation half-life and poor tumor accumulation. Additionally, photodynamic therapy (PDT) has been reported to synergize with immunotherapy, suggesting a potential combinatorial photodynamic immunometabolic cancer therapy with KYNase. Methods: A KYNase-Fc fusion protein was prepared to prolong blood circulation and enhance tumor accumulation of KYNase. Meanwhile, KYNase-Fc served as a nanocarrier for photosensitizer pheophorbide A (PhA) due to the high binding affinity between KYNase-Fc and PhA. Through self-assembly, KYNase-Fc/PhA nanoparticles (KYNase-Fc/PhA NPs) were prepared without extra carrier materials. Results: Compared with the PEGylated KYNase, KYNase-Fc exhibited significantly prolonged blood circulation, enhanced tumor accumulation and effective tumor suppression. Moreover, the prepared KYNase-Fc/PhA NPs facilitated rapid PhA tumor accumulation. The combined photodynamic immunometabolic therapy alleviated the immunosuppressive microenvironment and significantly inhibited the growth of subcutaneous 4T1 tumors in mice. Conclusions: KYNase-Fc offered a carrier-free nanomedicine for co-delivery of PhA for photodynamic immunometabolic antitumor therapy with enhanced efficacy, providing a promising platform for clinical translation. Full article

Rheumatoid arthritis involves chronic synovitis and immune-metabolic dysregulation, highlighting a need for multi-target therapies that jointly modulate metabolism and inflammation. We developed glycyrrhiza protein–paeoniflorin self-assembled nanoparticles (GP-PF NPs) and investigated their anti-arthritic mechanism in adjuvant-induced arthritis (AIA) mice, using UHPLC-Orbitrap-MS-based metabolomics. Male C57BL/6 mice (n = 42) were assigned to the control, model, GP-PF NPs, paeoniflorin, glycyrrhiza protein, physical mixture, and celecoxib groups. All groups except controls received complete Freund’s adjuvant, and treatments were given intraperitoneally for 10 days. GP-PF NPs produced the greatest reduction in paw thickness versus the model (p < 0.0001) and outperformed all other active treatments, which was consistent with the improved histopathology. UHPLC-Orbitrap-MS detected 473 serum metabolites, and the model group showed 59 significant changes versus the control. GP-PF NPs significantly modulated 108 metabolites and yielded robust OPLS-DA separation from the model (R²Y = 0.98; Q² = 0.742). Venn and pathway analyses identified 43 NP-specific metabolites enriched in glycerophospholipid metabolism, including glycerophosphocholine, 1-oleylglycerophosphocholine, PE (16:0/16:0), phosphocholine, and sphingosine-1-phosphate. These metabolites were selectively normalized toward control levels by GP-PF NPs. qPCR further showed that GP-PF NPs significantly reduced synovial PI3K, AKT, mTOR, NLRP3, Caspase-1, and GSDMD mRNA overexpression (all p < 0.001 vs. model). Correlation analysis indicated significant associations between key serum lipids and synovial genes (e.g., PI3K positively correlated with several metabolites, r = 0.71–0.82; mTOR negatively correlated with sphinganine 1-phosphate and glycerophosphocholine, r = −0.65 and −0.54). These data suggest that GP-PF NPs ameliorate AIA and are associated with the normalization of glycerophospholipid-related metabolic perturbations and reduced synovial mRNA expression of the PI3K/AKT/mTOR-NLRP3 pathway, supporting their potential as a metabolism-inflammation preclinical oriented anti-arthritic nanomedicine. Full article

As synthetic biology advances, prokaryotic microorganisms have become critical platforms for heterologous biosynthesis in cell factory applications. However, conventional free enzyme systems encounter substantial challenges, including inefficient intermediate transfer, toxic intermediate accumulation, and vulnerability to temperature and pH fluctuations. Enzyme complex catalytic systems offer promising solutions to these limitations. Bacillus licheniformis, a Generally Recognized as Safe (GRAS) host with exceptional protein secretion capacity, represents an ideal chassis for enzyme complex construction. This study developed a peptide-mediated platform in B. licheniformis to enable enzyme complex self-assembly and evaluated its effects on metabolic pathway performance. Five peptide elements were screened through fusion with enhanced orange/green fluorescent proteins (eOFP/eGFP) and transglutaminase (TGase). Effective peptide pairs were identified by measuring fluorescence intensity, visualizing complex formation via laser confocal microscopy, and assessing TGase activity. Subsequently, recombinant strains expressing peptide-fused key metabolic enzymes (gadTt and KdgA) were constructed for whole-cell biotransformation using gluconate as substrate to investigate the impact of peptide-mediated enzyme complexes on pyruvate synthesis. In the fluorescent protein system, P18/D18—amphipathic peptides that drive enzyme self-assembly via intermolecular hydrophobic interactions—increased extracellular fluorescence intensity of eOFP and eGFP by 31.11% and 25.21%, respectively. The D18 peptide significantly elevated TGase activity by enhancing structural stability to over 1.3-fold that of the control. For pyruvate synthesis, the peptide-mediated enzyme complex exhibited remarkable advantages in substrate conversion rate (up to 53.08%) and thermostability, confirming the platform’s ability to enhance substrate channeling despite no optimization for absolute yield. This study established a novel peptide-mediated multienzyme self-assembly platform in B. licheniformis, providing a valuable strategy for artificial metabolic channel design in synthetic biology. Full article

The interface between synthetic materials and biological systems is a critical determinant of performance in medical devices and biosensors. This review examines the evolution of biointerface science through the lens of self-assembled monolayers (SAMs) of thiols on gold, a model system that offers atomic-level control over surface chemistry. We trace the field from the foundational structural characterization to the establishment of empirical design rules for bio-inertness. While early theoretical models attributed protein resistance to steric repulsion forces in polymer brushes, contemporary understanding has shifted toward the “water barrier” hypothesis, which posits that tightly bound interfacial water prevents direct biomolecular contact. We highlight recent studies that extend these concepts into “realistic” crowded biological environments. Their work reveals that fouling surfaces in crowded media generate a “viscous interphase layer” (VIL) that extends tens of nanometers into solution, whereas zwitterionic surfaces maintain a robust hydration shell that prevents this accumulation. Furthermore, this hydration barrier is shown to fundamentally alter bacterial mechanics, forcing microorganisms into a reversible, tethered “hovering” state at a significant biological interaction distance (>100 nm) from the surface, effectively precluding biofilm nucleation. These insights underscore that the future of antifouling material design lies in the precise engineering of interfacial hydration structures. Full article

Inclusion bodies (IBs) in Escherichia coli are increasingly recognised as nanostructured materials with tunable morphology and functional potential. The N-terminal auxiliary activity family 10 (AA10) lytic polysaccharide monooxygenase (LPMO) domain from Caldibacillus cellulovorans (Ccel_p40) consistently forms IBs and, when fused to diverse proteins, generates functional IBs. Here, we examined whether this strong aggregation propensity is unique to Ccel_p40 or a broader feature of AA10 LPMOs. Four homologous domains from phylogenetically distinct microorganisms, Kallotenue papyrolyticum (Kpap_p40), Kibdelosporangium aridum (Kari_p40), Archangium lipolyticum (Alip_p40), and Phytohabitans suffuscus (Psuf_p40), were heterologously expressed in E. coli under identical cytosolic conditions. All homologues accumulated predominantly in the insoluble fraction, forming morphologically uniform IBs with sub-micron diameters (550–860 nm) and moderate polydispersity indices (0.45–0.54). SDS-PAGE densitometry indicated that most of each expressed protein partitioned into the insoluble fraction. Field-emission scanning electron microscopy revealed compact spherical aggregates, and Fourier-transform infrared spectroscopy showed β-sheet-enriched secondary structures characteristic of ordered IBs. These results indicate that the pronounced aggregation tendency previously observed for Ccel_p40 is conserved across the AA10 homologues examined. The findings support the view that the AA10 domain represents a promising scaffold for generating stable, recyclable protein nanoparticles and provides a comparative basis for future IB-based biotechnological designs. Full article

(1) Background: The synthetic eleven-amino acid peptide P₁₁-4, derived from DMP-1, self-assembles into β-sheet tapes, ribbons, fibrils, and fibers that form a 3D matrix enriched with calcium-binding sites. This study investigated whether P₁₁-4 modulates gene and protein expression or induces adverse metabolic alterations in odontoblast-like cells. (2) Methods: MDPC-23 cells were cultured under standard conditions and stimulated with different concentrations of P₁₁-4, followed by assessments of cell viability using the MTT assay, proliferation and migration, cytoplasmic calcium kinetics, reactive oxygen species (ROS) production, osteogenic differentiation-related gene expression via PCR array, and expression of the pro-inflammatory cytokine interleukin-6 (IL-6) using confocal microscopy and flow cytometry. (3) Results: The MTT assay showed that P₁₁-4 at 6.3, 12.6, and 25.2 µmol/L was non-cytotoxic and did not alter MDPC-23 cell proliferation or migration. Only the 25.2 µmol/L concentration induced a detectable Ca²⁺ influx and a slight increase in ROS. Among the 84 genes examined, P₁₁-4 at 6.3 µmol/L upregulated 79 genes, including transcription factors, signaling molecules, and extracellular matrix-related proteins. Furthermore, P₁₁-4 did not increase IL-6 expression under any condition tested. (4) Conclusion: P₁₁-4 markedly modulates mineralization-associated gene regulation without causing metabolic damage in odontoblast-like cells. Full article

BslA (Biofilm surface layer protein A), a highly hydrophobic lipoprotein from Bacillus spp., self-assembles at fluid interfaces to form a crystalline film that reduces surface tension. In this study, we selected Pichia pastoris as a eukaryotic system for expressing recombinant BslA identified in Bacillus paralicheniformis BL-1. The secretory expression of recombinant BslA in the P. pastoris GS115 strain under the AOX1 promoter was confirmed in shake-flask cultivation. Next, two fed-batch fermentation strategies, constant dissolved oxygen strategy (DO-stat) and oxygen-limited fed-batch (OLFB) strategy, in a 5 L scale, were compared. The DO-stat process led to late-stage cell death and product degradation, limiting yields. Switching to the OLFB process by removing the glycerol feeding phase mitigated this issue, allowing extended fermentation and increasing the final recombinant BslA concentration to 657 mg/L. This study establishes P. pastoris with an OLFB strategy as an effective system for secreting recombinant BslA protein, providing a basis for future industrial-scale production. Full article