ChemBioChem最新文献

The dark-operative protochlorophyllide oxidoreductase (DPOR) catalyzes the light-independent reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), a key step in photosynthetic pigment biosynthesis. Structurally and mechanistically related to nitrogenase, DPOR consists of a reductase (BchL) and a catalytic component (BchNB) homologous to the reductase (NifH) and catalytic component (NifDK) of Mo-nitrogenase. Structural alignment of Rhodobacter capsulatus (Rc) BchNB with Azotobacter vinelandii (Av) NifDK and the cofactor maturase NifEN reveals a conserved α₂β₂ architecture and a shared cofactor-insertion path linking their respective prosthetic-like group/cofactors (Pchlide, M-cluster, L-cluster), suggesting the possibility of generating chimeric proteins with novel reactivities. Herein, Pchlide-free RcBchNB (RcBchNB^apo) is reconstituted with the L-cluster extracted from AvNifEN to yield a hybrid protein (RcBchNB^L) capable of reducing N₂ and C₁ substrates (CN⁻, CO) to NH₃ and hydrocarbons, respectively, in the presence of a strong reductant (Eu^II-DTPA). In contrast, reconstituting Pchlide-bound RcBchNB with the L-cluster yields minimal activity, indicating that Pchlide and the L-cluster compete for a common binding site, as supported by Boltz-2 modeling. These findings support the hypothesis of an intertwined evolution of photosynthetic and nitrogen-fixing enzymes and outline a framework for engineering chimeric metalloenzymes that couple light capture with nitrogenase-like catalysis in the future.

Kakkis, A.; Sun, L.; Xie, Z.; Qaddourah, M.; Dawson, P. E.; Sanchez, B. B.; Orzolek, B. J.; Brunel, F. M.; Stock, J. R.; Kolakowski, R. V.; Korboukh, I.; Leon, J. C. Synthesis of Chemically Diverse siRNA-Lipid Conjugates Enabled by Reversible Adsorption to Solid Support (RASS). ChemBioChem 2025, 26 (13), e202500169. https://doi.org/10.1002/cbic.202500169.

The order of authors was incorrect. P. E. Dawson should have been listed last, as the corresponding author.

The funding acknowledgement was incomplete. It should have noted that A. Kakkis was supported through an NIH T32 training grant (5T32AA007456-43).

We apologize for these errors.

Growing interest in sustainable nutrition has improved the importance of understanding the interactions between (-)-Epigallocatechin-3-gallate (EGCG), a polyphenol in green tea, and proteins for functional food development. In this study, we investigated the regulatory effects of EGCG on the aggregation behavior of zein, ovalbumin, and their complexes. The addition of EGCG at 100 μg mL⁻¹ led to significant changes in particle sizes of zein, ovalbumin, and zein-ovalbumin complexes, increasing them from 215.6, 3485.3, and 2081.0 nm to 4822.3, 7857.0, and 5895.7 nm, respectively. The zeta potentials of these samples decreased from 8.4, −2.6, and 5.0 mV to −5.3, −0.66, and 2.13 mV, respectively, indicating a reduction in net surface charges and promotion of protein aggregation. UV–vis absorption spectroscopy revealed hyperchromic effects and blue shifts upon EGCG addition, suggesting conformational changes. Molecular dynamics simulations further revealed that EGCG contributed to the structural stabilization of both individual proteins and their complexes by reinforcing hydrophobic and electrostatic contacts at the molecular interface. These findings provide molecular-level insights into the regulatory role of EGCG in protein assembly and offer guidance for the rational design of plant-animal protein complexes with tailored functional properties for food applications.

Expanding the chemical repertoire of canonical nucleotides is key to unlocking the full functional potential of aptamers for diagnostic use. Herein, click-systematic evolution of ligands by exponential enrichment (SELEX) is employed to generate chemically modified DNA aptamers, termed clickmers, that target the SARS-CoV-2 spike (CoV2-S) glycoprotein. Two independent split-combine selection strategies yield distinct clickmer families functionalized with benzofuran or indole moieties. Lead candidates (BF1 and N2) demonstrate nanomolar affinity for wild-type CoV2-S and maintain binding to multiple variants, including Alpha, Delta, and Mu, as validated by flow cytometry, surface plasmon resonance, and microscale thermophoresis. Structure–function analysis reveals essential click-in positions for both full-length clickmers and a truncated N2 variant, as short as 31 nucleotides, which displays increased binding to the Omicron variant. These results highlight the versatility of the click-SELEX platform and exemplify its successful application to a clinically relevant target, advancing previous developments in the field.

Purines and their receptors play a role in the regulation of stem cell survival, proliferation, and differentiation. They are responsible for the osteogenic differentiation of stem cells by activating many signaling pathways and enhancing the expression of different osteogenic factors, including bone morphogenetic proteins, runt-related transcription factor 3, alkaline phosphatase (ALP), etc. Here, a 2,6,9-trisubstituted adenine derivative is reported, with negligible cytotoxicity and potent osteogenic potential as demonstrated with mouse myoblast (C2C12 cells) and murine preosteoblasts (MC3T3E1 cells). Osteogenic activity of the derivative (Compound 1) is supported by increased expression of ALP and enhanced calcium deposition observed with alizarin staining within cells. Thus, the reported adenine derivatives can serve as potential therapeutics for bone fractures as an injectable therapeutic opening avenue for cell-free therapy.

Library-on-library (LOL) selection screens combinatorial libraries to generate new protein pairs. Previously, LOL selection has only been applied to stable protein–protein interactions. To extend LOL to transient enzyme–substrate pairs, a generalizable sequential LOL trans- and cis-labeling platform is developed, and a proof-of-concept selection is performed on Escherichia coli biotin ligase (BirA) and its acceptor peptide (AP). Using yeast surface display, AP mutant libraries are selected against BirA mutant libraries to identify AP variants trans-biotinylated by BirA mutants. Matched BirA mutants are subsequently enriched via the SpyTag–SpyCatcher-mediated cis-labeling platform. This represents the first demonstration of enzyme–peptide substrate LOL selection and offers a versatile framework for engineering new enzyme–peptide substrate pairs with varied activities.

Metal–organic frameworks (MOFs) have emerged as highly tunable materials for targeted and controlled drug delivery. In this study, NUIG4 is presented as a multifunctional MOF-based carrier capable of encapsulating both anticancer and antimicrobial therapeutics. NUIG4 exhibits high-surface area, water stability, and suitable porosity, supporting the efficient loading of a range of drug molecules. Its dual anticancer drug delivery performance is assessed using doxorubicin (DOX) and 5-fluorouracil (5-FU). Co-loading studies demonstrate successful encapsulation of both drugs and synergistic cytotoxicity in MDA-MB-231 breast cancer cells, indicating that the MOF preserves and potentially enhances the therapeutic efficacy of both drugs. Furthermore, NUIG4 is assessed as a carrier for antibiotics, including tetracycline (TET), isoniazid (INH), and pyrazinamide (PYZ), demonstrating sustained, pH-responsive release. TET@NUIG4 retain potent antimicrobial activity against S. aureus and E. coli, with minimum inhibition concentration values matching those of the free drug, while INH and PYZ highlight NUIG4's potential for tuberculosis-directed delivery. Spectroscopic analyses and kinetic modeling support a chemisorption-based mechanism and efficient, sustained release. These findings establish NUIG4 as one of the few MOFs reported, capable of both dual anticancer drug codelivery and antibiotic encapsulation and release, suitable for targeting both cancer and infectious diseases.

The RXFP3/Relaxin-3 system is implicated in behaviors such as addiction, anxiety and depression, making it an attractive pharmaceutical target. Because RXFP3 is primarily located in the central nervous system, achieving blood–brain barrier penetration is crucial. The cover depicts the relaxin family peptide receptor 3 and its ligand relaxin-3 in the bottom left corner, with key reported small molecules shown in white. The alpha helix in the background represents recently developed single-chain peptidomimetics. More details can be found in the Research Article by Mohammed Akhter Hossain and co-workers (DOI: 10.1002/cbic.202500664).

This image depicts the mechanism of Photo-induced Duplex Invasion (pDI). The artwork illustrates how a single invading strand, modified with the 3-cyanovinylcarbazole nucleoside (^CNVK), targets long double-stranded DNA. Under UV irradiation, this modification enables the strand to rapidly open the DNA helix and cross-link to its target sequence. This visual demonstrates the high efficiency of the pDI strategy for recognizing specific genetic sequences, holding significant potential for applications in biotechnology and genomic engineering. More details can be found in the Research Article by Kenzo Fujimoto and co-workers (DOI: 10.1002/cbic.202500626).

Polyketides constitute a large class of natural products with important biological activities and applications such as antibiotics, antitumor agents, pesticides, and pigments. Their biosynthesis is catalyzed by polyketide synthases (PKSs) which are multidomain enzymes evolutionarily related to fatty acid synthases (FASs). Despite their close homology in structure and the chemistry they perform, FASs and PKSs differ fundamentally in their catalytic programming: FASs run fully reducing elongation reactions to yield saturated fatty acids, while iterative PKSs execute reductions just in selected cycles, generating complex oxidized compounds. In this study, we aimed at engineering the metazoan FAS in its ketoreduction (KR) domain to switch from fully reducing to a nonreducing mode during chain elongation. Guided by recent insights into KR programming, we incorporated a helix into metazoan FAS, which is found in KRs from iterative PKSs and type II FASs with chain length programming. These FAS variants initially catalyze complete fatty acid cycles but lose the ability of β-keto reduction in later elongation rounds, producing intermediates that spontaneously cyclize to pyrone products. Finally, our study provides valuable insight into the mechanism of KR catalysis identifying another amino acid next to the active tyrosine which is capable for intermediate protonation.