化学最新文献

Liquid-liquid phase separation (LLPS) is involved in both the self-assembly of vital cellular organelles and the disease-associated protein misfolding, where LLPS precedes a liquid-solid phase transition (LSPT) leading to amyloid aggregates. Chimeric ACC_1-13K_n peptides are insightful models to study coupled LLPS/LSPT processes triggered by ATP-binding. Here, we investigated the impact of macromolecular crowding on the selection of the aggregation pathway in the ACC_1-13K₈-ATP system. While it has been previously shown that peptides with relatively short oligolysine segments (K₁₆ and shorter) skip the LLPS stage on their pathway to amyloid fibrils, we show here that concentrated polyethylene glycol (PEG), mimicking intracellular crowding conditions, induces prior formation of liquid droplets that subsequently facilitate fibril formation. The influence of PEG contrasts with the behavior of other types of macromolecular crowding agents, Dextran and Ficoll, which accelerate aggregation without a detectable LLPS phase, and that of serum albumin, which prolongs the nucleation phase. In the presence of PEG-induced macromolecular crowding, the fibrillization in the ACC_1-13K₈-ATP system appears to reach a maximal rate limited by diffusion coupled to the conformational dynamics of the polypeptide chains within the droplets. Importantly, the ACC_1-13K₈-ATP fibrils formed in the presence of PEG are distinct from those of the ACC_1-13K₈-ATP amyloid formed in the absence of crowding in terms of their infrared characteristics, morphological features, and overall stability. Our findings suggest that macromolecular crowding can switch between kinetically and thermodynamically favored amyloid polymorphs and that the chemical properties of the crowding agents are key factors in their impact on protein aggregation processes. The results are discussed in the context of the mechanisms of LLPS-dependent protein misfolding and amyloid formation.

Therapeutic interventions for complex diseases depend on the targeted modulation of key pathological pathways. While growing clinical needs continue to drive advancements in the drug discovery space, current strategies primarily rely on searching large volumes of chemical data without addressing the specific contributions of molecular features. Moreover, both clinicians and researchers recognize the need for improved drug discovery methods and characterization that could aid in clinical strategy selection. To address these challenges, we propose a new perspective on targeted therapy development as well as interactome mapping, utilizing molecular fragments. The present study focuses on therapeutic areas that represent emerging targets, namely JAK2 and GLP-1R, both of which have broad clinical potential. We developed a new self-adjusting neural network that enabled us to discover novel therapeutic candidates with improved in silico binding profiles, gain additional insights into drug-target binding that were not previously reported, and identify new metabolic trajectories. Importantly, our work revealed that even a small compound library can effectively generate lead candidates, expediting the search and exploration process. In addition, the fragment-guided bridging of chemical and biological spaces has revealed new opportunities for drug repurposing efforts and a means of improving the prediction of side effects. We concluded our study with insights into the recent high-profile clinical trial failure of danuglipron and how this could have been prevented with our methodology. Thus, building a robust in silico pipeline with integrated screening data can significantly reduce costs and guide therapy adoption. Furthermore, our proposed strategy highlights promising avenues for the discovery of new therapeutics and the development of clinical interventions.

Cysteine fluorescent probes are specialized molecular tools that facilitate highly sensitive detection of cysteine via alterations in fluorescent signals. Currently, these probes have been widely employed in fields including disease biomarker monitoring, redox balance research, and drug toxicity assessment, thereby exhibiting substantial application potential in biochemical and biomedical studies. In this study, a novel fluorescent probe was designed for detecting cysteine based on the thiopyrone structure. Through characterization of its properties, it was found that this fluorescent probe exhibits a large Stokes shift (217 nm), excellent sensitivity (13.60 nM), rapid response time (3.0 min), high stability and selectivity. Furthermore, this cysteine fluorescent probe demonstrates excellent applications in RAW 264.7 cells, zebrafish, and actual samples. This study also proposes a more convenient method for testing cysteine levels using mobile phone software, and the findings indicate that the fluorescent probe under investigation has considerable potential for use in cysteine detection.

The accurate diagnosis of anxiety disorders remains challenging, as current detection methods primarily rely on subjective questionnaires. In this study, a novel electrochemical biosensor for the detection of fibroblast growth factor-2 (FGF-2), a biomarker associated with anxiety disorders, was developed for the first time. The sensing principle was based on monitoring the impedimetric signal changes generated by the interaction between anti-FGF-2 and the FGF-2 antigen, using a carbon screen-printed electrode as the transducer. To enhance the sensitivity and overall performance of the biosensor, a multi-walled carbon nanotube-gold-platinum (MWCNT-Au-Pt) hybrid nanocomposite was incorporated into the immunosensor structure. Critical parameters-including the amount of MWCNT-Au-Pt, the concentration, incubation time, and temperature of anti-FGF-2, as well as the incubation time and temperature for the anti-FGF-2/FGF-2 interaction-were systematically optimized. Under optimized conditions, the developed impedimetric FGF-2 immunosensor exhibited a linear response in the range of 10-100 ng/mL, with a limit of detection of 1.01 ng/mL and a limit of quantification of 3.10 ng/mL. The specificity of the sensor was confirmed in the presence of potential interfering substances. For real sample analysis, human saliva samples (n = 30) were diluted appropriately and spiked with FGF-2 at concentrations of 20, 50, and 75 ng/mL. The obtained recovery values demonstrated that the developed impedimetric FGF-2 immunosensor is highly suitable for real-sample applications and holds significant potential as a reliable tool for the detection of anxiety disorders.