ChemBioChem最新文献

The rapid emergence of antibiotic resistance has rendered many conventional antibiotics ineffective, complicating the management of bacterial infections and leading to severe community- and hospital-acquired diseases. This growing resistance crisis poses a major threat to global public health and the stability of healthcare systems. Metal-based nanoparticles have recently gained significant attention as alternative antibacterial agents because of their broad-spectrum activity and low likelihood of inducing bacterial resistance. However, their clinical translation remains limited by nonspecific cytotoxicity and poor biocompatibility, which can adversely affect mammalian cells. To overcome these challenges, recent research has focused on engineering strategies that enhance the biocompatibility of metal nanoparticles (MNPs) without compromising their antibacterial efficacy. This review summarizes the latest advances in the rational design, surface modification, and functionalization of biocompatible metal-based nanoplatforms for infection treatment. Themechanisms of antibacterial action, approaches to minimize off-target toxicity, and potential clinical application. Together, these insights highlight the promise of engineered MNPs as next-generation antibacterial therapeutics capable of addressing the escalating threat of multidrug-resistant infections.

The prion concept fundamentally signifies the intrinsic cross-seeding potential of misfolded protein-generated amyloid entities to efficiently induce amyloid aggregation in normally folded proteins leading to formation of cytotoxic amyloid structures. A conformational crosstalk between the prion particle and the interacting protein appears critical for the molecular origin of seeded-aggregation. However, the intricacies of protein specificity, as a prerequisite for the onset of cross-seeding, hold negligible relevance to the pathobiology of amyloid-linked diseases because the amyloid-deposits are heteroprotein assemblies, and there is adequate evidence that substantiates the occurrence of sequence-independent amyloid-cross-seeding/co-aggregation reactions between diverse protein types. Importantly, extensive research on the self-assembly of single metabolites into cytotoxic amyloid-like entities containing cross-seeding competent conformers has certainly widened the boundary of prion concept much beyond the territory of proteins and peptides. Three important observations: 1) sequence-independent cross-seeding and co-aggregation among proteins; 2) efficient amyloid-cross-seeding of proteins triggered by self-assembled metabolite-nanostructures, and 3) molecular self-assembly of metabolites induced by pre-formed protein amyloid-seeds, propose a synergetic interplay between the amyloidogenic proteins and self-assembly-prone metabolites that can act as a key regulator for the overall amyloidogenesis mechanism. This review on the self-assembly of biologically relevant metabolites into amyloid-mimicking nanostructures mainly highlights their cytotoxic properties and cross-seeding potential, particularly focusing on the significance of the metabolite-aggregation in the etiology of amyloid hypothesis.

Hypoxia bioimaging attracts tremendous attention due to its profound implications in diagnosis of a range of pathological conditions. Nitroaromatics-based fluorescent probes are the most popular approach to tackle this problem. Despite intensive efforts of the field over the past 15 years and the development of a range of such probes, three challenges are still not addressed, i.e., highly sensitive probes necessitating a one-electron reduction, real-time monitoring probes with reversible sensing capability, and near-infrared probes with in vivo imaging potentials. Three groups have recently reported notable progresses regarding these challenges, which may spur another wave of development along this line of research and meet the need of real-world applications from researchers and doctors.

This study presents a robust bioprocess for the global incorporation of noncanonical amino acids (ncAAs) into proteins, enabling gram-scale production in auxotrophic Escherichia coli strains. The two-phase approach adapts from shake flask to bioreactor cultures and relies on cost-effective synthetic minimal media with glucose as the sole carbon source and yeast extract as an amino acid supply. It supports both external ncAA supplementation and in situ biosynthesis. A versatile E. coli BL21(DE3) auxotroph platform ensures broad ncAA and protein compatibility. Model proteins, such as a thermophilic lipase (TTL) and an oxidoreductase are labeled with biosynthesized norleucine (Nle), synthetic fluoroprolines, and fluorophenylalanine. Under optimal conditions, we achieved titers of up to 2 g L⁻¹ with near-quantitative incorporation. To demonstrate the utility of the bioprocess for applications that require substantial amounts of proteins, the crystal structure of Nle-labeled TTL is solved. Future work should optimize media composition and feeding strategies to improve ncAA bioavailability and integrate biosynthesis pathways into the host genome to reduce metabolic burden and eliminate antibiotic use. These advances will make the process a cost-effective industrial platform for designer protein production.

Herein, an enzymatic in vitro synthesis route to indigo, the dye that gives denim its renowned color, is described. The proposed five-step enzymatic pathway is derived from the natural biosynthesis route starts from anthranilate. In the context of the bio-based economy, this method provides an alternative to the current method of indigo synthesis, which relies on petroleum-based building blocks. First, the enzymes are assessed by stepwise addition to detect intermediate compounds, to ensure cascade function. A two-phase system is designed in response to differences in melting temperatures of the enzymes. A titer of 183 mg L⁻¹ indigo is reached through stepwise parameter optimization for each phase, followed by process engineering to enhance the indigo titer. Continuous supplementation of the cosubstrate phosphoribosyl pyrophosphate is necessary to maintain indole-3-glycerol phosphate (IGP) formation in the first phase. During the second phase, complete uptake of IGP by ZmBX1 remains challenging, and formation of significant byproducts is observed. Despite attempts to resolve these issues, the underlying mechanism remains unclear. Although the yield must be significantly improved for an economically viable process, an enzymatic cascade based on bio-based materials remains a potential alternative for sustainable denim dye synthesis by circumventing host toxicity observed in whole-cell approaches.

Radiopharmaceuticals (RPhs) represent a breakthrough in nuclear medicine due to their ability to provide precise diagnosis and targeted therapy for cancer by incorporating radioactive isotopes into carrier molecules. This review systematically discusses the recent advances in the development of RPhs, focusing on state-of-the-art probe design strategies and click chemistry applications that accelerate RPh syntheses and improve targeting efficiency. The manuscript synthesizes literature from multiple databases spanning January 2014 to April 2025, encompassing diagnostic modalities including positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging, and therapeutic applications utilizing alpha and beta emitters such as ²²⁵Ac and ¹⁷⁷Lu. Clinically approved agents, such as ¹⁷⁷Lu-DOTATATE and ¹⁷⁷Lu-PSMA-617, are used for neuroendocrine tumors and metastatic castration-resistant prostate cancer, respectively, with significant therapeutic efficacy. The review focuses on new targets, such as fibroblast activation protein, CXCR4 chemokine receptors, and gastrin-releasing peptide receptors, and new delivery systems using nanotechnology to improve biodistribution and tumor accumulation. Challenges regarding production scalability, regulatory frameworks, and integrating artificial intelligence for personalized dosimetry and treatment planning remain crucial. Combination therapeutic approaches using targeted radionuclide therapy (TRT) in synergy with chemotherapy and immunotherapy and external beam radiation are showing promising results in refractory cancers. The potential avenues include theranostics, predictive modeling for patient selection, and new molecular targeting strategies. This review highlights the transformative potential of RPhs in precision oncology, providing an overview of the current clinical applications and future research trajectories toward improved cancer management.

Microfluidics is a very attractive discipline for implementing more versatile high-throughput screening methods to improve enzymes. However, state-of-the-art microfluidics set-ups are mainly devoted to screening enzymes in solution, while screening of enzyme immobilization protocols using microfluidics is scarce. In this work, a microreactor device is designed, fabricated and applied to test different heterogeneous biocatalysts with transaminase activity. This microsystem set-up can be operated in two different modes: packed-bed (PBR) and fluidized (FBR) microreactors without exchanging the sample. Using the same sample to run the two modes, the fidelity of the comparison is increased between the two fluid dynamic regimes. Moreover, by testing different carriers under different modes, a Histagged transaminase is found from Pseudomonas fluorescens immobilized on agarose porous microbeads functionalized with cobalt-chelates and operated as FBR maximizes the STY, and minimizes the equilibration times. This device exemplifies the potential of microreactors for prototyping more efficient heterogeneous biocatalysts.

Therapies targeting amyloid β (Aβ), especially promoting Aβ clearance, have attracted increasing attention in treating Alzheimer's disease (AD). However, the regulatory factors in Aβ metabolism remain poorly understood. Herein, three homogeneously glycosylated Aβ₄₂ peptides are utilized to explore the impacts of Tyr10 O-glycosylation on Aβ clearance in astrocytes. Based on various biochemical and cellular assays, it is shown that the introduced α-O-glycan stabilizes the Aβ oligomers and enhances Aβ₄₂ endocytosis and autophagy in astrocytes, which ultimately promotes the intracellular degradation of Aβ₄₂ and the secretion of Aβ-degrading enzymes. Particularly, a disaccharide, Galβ1-3GalNAc, exhibits the most substantial clearance-enhancing effect. Moreover, experiments with AD-like model mice show protective effects from the disaccharide modification in alleviating Aβ₄₂-induced impairment of spatial cognitive performance. Thus, beyond showing the influences induced by particular O-glycosylation on Aβ₄₂ degradation, the study provides implications of a possible role of Tyr10 O-glycan in regulating Aβ clearance in the brain.

The question of lanthanide (Ln) uptake in Ln-using bacteria has gained a lot of attention in recent years, and the existence of specific Ln-binding metallophores, termed lanthanophores, has been postulated. Here, the recently isolated metallophore methylolanthanin (MLL), which is shown to be involved in Ln metabolism of Methylobacterium extorquens AM1 along the structurally related siderophore rhodopetrobactin B (RPB B), is investigated. The total synthesis of both chelators as well as Ln-binding investigations employing a multitude of spectroscopic methods is reported. Compared to MLL, RPB B has a higher binding affinity for Fe³⁺. Unexpectedly, both metallophores seem to precipitate Lns under biologically relevant conditions (pH and concentration range). Therefore, a solubility product of −12.07 ± 0.24 mol² L⁻² for the precipitated Eu³⁺-MLL complex is reported. Furthermore, a combination of single-cell inductively coupled plasma mass spectrometry and Liquid Chromatography-Mass Spectrometry (LC-MS) analysis of bacterial supernatant to investigate the Nd accumulation as well as MLL secretion under Fe limitation in M. extorquens AM1 is used. Finally, ion mobility spectrometry-mass spectrometry and quantum chemical calculations are used to investigate the RPB B and MLL complexation in the gas phase with Fe³⁺ and all rare earth elements (except Pm). The results challenge the classical siderophore-like Ln uptake (via simple solubilization) through MLL and underline again a potential complex interplay between Fe³⁺ and Ln³⁺ in microbial Ln uptake.

Human inflammatory caspases (caspase-1, -4, and -5) are key players in the innate immune response. These enzymes have been shown to cleave proinflammatory substrates, implicating them in many inflammatory disease states. Their activity is frequently assessed using in vitro fluorogenic assays, with all three human inflammatory caspases preferring the same WEHD tetrapeptide. The study examines the specificity of these enzymes C-terminal to the cleaved aspartate residue with Förster resonance energy transfer peptide-based assays using 7-methoxycoumaryl alanine [A(MCA)] as the donor and lysine-conjugated dabsyl [K(Dab)] as the quencher. The P₄–P₁ peptide sequences A(MCA)EHD, A(MCA)VAD, and A(MCA)QPD are varied on the C-terminal (prime) side of the peptide. Historically, caspase-4 and caspase-5 have been grouped together in their reactivity. Herein, caspase-5 only appreciably cleaves the A(MCA)EHDGK(Dab) peptide, whereas caspase-4 displays broader reactivity. All base sequences react more considerably with caspase-4 when a glycine is included C-terminal to Asp. The specificity of caspase-1 at this position varies based on the P₃–P₁ sequence of the peptide. These results highlight the interconnectedness of the prime and nonprime side amino acid sequences and the different behavior of each enzyme, which can be useful in understanding these potential drug targets.