ChemBioChem最新文献

4-Hydroxyisochroman-1-ones belong to the class of the secondary metabolite 3,4-dihydroisocoumarins. They exhibit a wide range of biological activities. These compounds can be synthesized through halocyclization using hypervalent iodine species or N-bromosuccinimide, followed by hydrolysis. Nonetheless, the reactions required specific conditions and generated toxic byproducts. In this study, Curvularia inaequalis vanadium chloroperoxidase (CiVCPO) catalyzed the chemoenzymatic cyclization of 2-vinylbenzoic acids with different electron-donating groups (1 a-1 e) to produce good yields of 4-hydroxyisochroman-1-ones (3 a-3 e) by adding KBr and H₂O₂ in citrate buffer (pH 5). The reaction mixture contained 30 % DMSO to improve substrate solubility without enzyme activity loss. The condition is more environmentally friendly than chemical methods. Therefore, it offers an alternative approach for synthesizing 4-hydroxyisochroman-1-ones.

Modular type I polyketide synthases (PKSs) are remarkable molecular machines that can synthesize structurally complex polyketide natural products with a wide range of biological activities. In these molecular machines, ketosynthase (KS) domains play a central role, typically by catalyzing decarboxylative Claisen condensation for polyketide chain extension. Noncanonical KS domains with catalytic functions rather than Claisen condensation have increasingly been evidenced, further demonstrating the capability of type I PKSs for structural diversity. This review provides an overview of the reactions involving unusual KS activities, including PKS priming, acyl transfer, Dieckmann condensation, Michael addition, aldol-lactonization bicyclization, C-N bond formation and decarbonylation. Insights into these reactions can deepen the understanding of PKS-based assembly line chemistry and guide the efforts for rational engineering of polyketide-related molecules.

Liquid-liquid phase separation (LLPS) refers to a spontaneous separation behavior of biomacromolecules under specific physiological conditions, playing a crucial role in regulating various biological processes. Recent advances in synthetic peptides have greatly improved our understanding of peptide-based coacervate droplets and expanded their applications in biomedicine. Numerous peptide sequences have been reported that undergo phase separation, enabling the concentration and sequestration of different guest molecules for purposes such as drug delivery, catalytic performance, and bioanalytical techniques. Particularly, some of these peptides offer significant advantages in controlled drug release, efficient cell transfection, accelerated reaction kinetics, and selective biomarker detection. This review provides an overview of recent developments in peptide-based LLPS, exploring various strategies for designing peptide sequences and their biomedical applications. It also addresses the challenges and future directions for LLPS peptide vehicles as promising biomaterials.

Isocyanates are versatile electrophiles that can react with a wide range of nucleophiles to afford important organic structures. Although the reactions between isocyanates and alcohols, amines and organometallic reagents have been well established, the synthesis of amides through the decarboxylative condensation of carboxylic acids and isocyanates is less appreciated. In this review, the synthesis of isocyanates and its application on amide synthesis through the condensation with carboxylic acids are summarized and discussed. It is our hope that this review will attract more attention to this less mentioned transformation and inspire new developments in the fields of organic synthesis, polymer synthesis and chemical biology.

Chromopyrrolic acid (CPA) and its congeners are important intermediates for the biosynthesis and synthesis of various dimeric tryptophan natural products. We have constructed two E. coli strains (CPA001/CPA002) harboring a single plasmid carrying genes coding for a combination of two enzymes (LaStaO/LzrO and VioB) that are able to convert L-tryptophan (L-Trp)/5-chloro-L-tryotophan (5-Cl-L-Trp) to chromopyrrolic acid (CPA)/5,5'-dichloro-chromopyrrolic acid (5,5'-diCl-CPA). Effect on the production of CPA were evaluated by varying the parameters of strain cultivation and biotransformation process. Under the optimized conditions, up to 325 mg/L of CPA and 275 mg/L of 5,5'-diCl-CPA could be obtained by supplementing L-Trp and 5-Cl-L-Trp, respectively, to a working culture of CPA001, or to a phosphate buffer-resuspended culture of CPA002. The practicability of this whole-cell biotransformation system could also be served as a potential platform for the preparation of CPA congeners.

Enzymatic degradation of polymers holds promise for advancing towards a bio-based economy. However, the bulky nature of polymers presents challenges in accessibility for biocatalysts, hindering depolymerization reactions. Beyond the impact of crystallinity, polymer chains can reside in different conformations affecting binding efficiency to the enzyme active site. We previously showed that the gauche and trans chain conformers associated with crystalline and amorphous regions of the synthetic polyethylene terephthalate (PET) display different affinity to PETase, thus affecting the depolymerization rate. However, structural-function relationships for biopolymers remain poorly understood in biocatalysis. In this study, we explored the biodegradation of previously synthesized bio-polyesters made from a rigid bicyclic chiral terpene-based diol and copolymerized with various renewable diesters. Herein, four of those polyesters spanning from semi-aromatic to aliphatic were subjected to enzymatic degradations in concert with induced-fit docking (IFD) analyses. The monomer yield following enzymatic depolymerization by IsPETase S238 A, Dura and LCC ranged from 2 % to 17 % without any further pre-treatment step. The degradation efficiency was found to correlate with the extent of matched substrate and enzyme conformations revealed by IFD, regardless of the actual reaction temperature employed. Our findings demonstrate the importance of conformational selection in enzymatic depolymerization of biopolymers. A straight or twisted conformation of the polymer chain is crucial in biocatalytic degradation by showing different affinities to enzyme ground-state conformers. This work highlights the importance of considering the conformational match between the polymer and the enzyme to optimize the biocatalytic degradation efficiency of biopolymers, providing valuable insights for the development of sustainable bioprocesses.

Recent advances in computational methods like AlphaFold have transformed structural biology, enabling accurate modeling of protein complexes and driving applications in drug discovery and protein engineering. However, predicting the structure of systems involving weak, transient, or dynamic interactions, or of complexes with disordered regions, remains challenging. Nuclear Magnetic Resonance (NMR) spectroscopy offers atomic-level insights into biomolecular complexes, even in weakly interacting and dynamic systems. Paramagnetic NMR, in particular, provides long-range structural restraints, easily exceeding distances over 25 Å, making it ideal for studying large protein complexes. Advances in chemical tools for introducing paramagnetic tags into proteins, combined with progress in electron paramagnetic resonance (EPR) spectroscopy, have enhanced the method's utility. This perspective article discusses paramagnetic NMR approaches for analyzing biomolecular complexes in solution and in the solid state, emphasizing quantities like pseudocontact shifts, residual dipolar couplings, and paramagnetic relaxation enhancements. Additionally, dynamic nuclear polarization offers a promising method to amplify NMR signals of large complexes, even in complex environments. The integration of AlphaFold protein structure prediction with paramagnetic NMR holds great potential for advancing our understanding of biomolecular interactions.

Nucleotide sugars (NSs) are essential building blocks for the enzymatic assembly of glycans. In this study, we established a preparation and recycling avenue to the biocatalysts for the enzymatic synthesis of NSs. This approach involves fusing two enzymes into a bifunctional chimera and using elastin-like polypeptides (ET64) as a purification tag, which allows for easy recovery of these biocatalysts without the need for chromatography. We successfully constructed and obtained five bifunctional fusion enzymes (GalK-USP-ET64, GlmU-NahK-ET64, ManC-NahK-ET64, FKP-ET64, and NanA-CSS-ET64) for the synthesis of five common NSs (UDP-Gal, UDP-GlcNAc, GDP-Man, GDP-Fuc, and CMP-Neu5Ac). These enzymes were obtained using the Inverse Transition Cycling (ITC) process in yields ranging from 60 to 124 mg per liter of fermentation. The enzymatic synthesis of NSs was carried out on a scale from hundreds of milligrams to multiple grams using these biocatalysts. Furthermore, we investigated the reusability of these biocatalysts by recycling them from the reaction solution using the ITC process. The recycling of GalK-USP-ET64, GlmU-NahK-ET64, FKP-ET64, and NanA-CSS-ET64 was effectively achieved for 15, 13, 3, and 4 times, respectively. These biocatalysts could be used not only for the enzymatic synthesis of NSs but also for the chemoenzymatic synthesis of glycan biomolecules when coupled with glycosyltransferases.

The evolution of antitumor drug development has transitioned from single-agent chemotherapy to targeted therapy, immunotherapy, and more recently, multispecific drugs. These innovative drugs target multiple cellular or molecular pathways simultaneously, offering a more comprehensive anticancer approach and addressing some of the limitations inherent in traditional monotherapies. However, preclinical assessment of multispecific drugs remains challenging, as conventional tumor models often lack the necessary complexity to accurately reflect the interactions between various cell types and targets. Patient-derived immunocompetent tumor organoids (PDITOs), which incorporate both tumor cells and immune cells, present a promising platform for the evaluation of these drugs. Beyond their use in drug evaluation, PDITOs can also be utilized in personalized drug screening and predicting patient-specific treatment outcomes, thus advancing both multispecific drug development and precision medicine. This perspective discusses the current landscape of multispecific drug development and the methodologies for constructing PDITOs. It also addresses the associated challenges and introduces the concept of employing these organoids to optimize the evaluation and rational design of multispecific drug therapies.

The resistance of cancer cells to apoptosis poses a significant challenge in cancer therapy, driving the exploration of alternative cell death pathways such as pyroptosis, known for its rapid and potent effects. While initial efforts focused on chemotherapy-induced pyroptosis, concerns about systemic inflammation highlight the need for precise activation strategies. Photothermal therapy emerges as a promising non-invasive technique, minimizing pyroptosis-related side effects by targeting tumors spatially and temporally. However, accurately pinpointing tumors to avoid collateral damage remains a challenge. Thus, we utilize NIR-II fluorescence imaging to achieve precise PTT-induced pyroptosis activation in glioma. A polymer semiconductor-based PTT agent was developed with high optical stability, integrated with mesoporous silica to enhance its biocompatibility. These nanoparticles, stabilized through PEG modification and targeted with cRGD peptides, effectively induced pyroptosis in vitro. Furthermore, this design facilitated precise tumor imaging guidance and subsequent pyroptosis activation in vivo, presenting a promising strategy for glioma therapy with minimized adverse effects.