Bioconjugate Chemistry最新文献

Post-translational modifications (PTMs) on histones play a crucial role in determining the structure and function of chromatin, thereby regulating the eukaryotic gene expression. Histone lysine methylation and acetylation are among the most widespread and biomedically important PTMs, with new chemical tools for their examination in high demand. Here, we report the first use of γ-selenalysine as an efficient lysine mimic for enzymatic methylation, acetylation, and deacetylation reactions catalyzed by histone lysine methyltransferases, acetyltransferases, and a deacetylase. We also show that easily accessible selenocysteine and cysteine residues can undergo chemo- and site-selective alkylation reactions to generate both unmodified and modified γ-selenalysine and related γ-thialysine residues in histone peptides. This dual-modification strategy enables the site-specific incorporation of two distinct functionalities into peptides, mimicking lysine post-translational modifications commonly found on histones. Our research presents a novel approach in which selenocysteine serves as a unique handle for the chemoselective introduction of selenalysine, along with its methylated and acetylated analogues. These tools are designed to facilitate the study of epigenetic proteins that are important for human health and disease.

Nucleic acid nanoparticles (NANPs) fabricated by using the DNA origami method have broad utility in materials science and bioengineering. Their site-specific, heterovalent functionalization with secondary molecules such as proteins or fluorophores is a unique feature of this technology that drives its utility. Currently, however, there are few chemistries that enable fast, efficient covalent functionalization of NANPs with a broad conjugate scope and heterovalency. To address this need, we introduce synthetic methods to access inverse electron-demand Diels-Alder chemistry on NANPs. We demonstrate a broad conjugate scope, characterize application-relevant kinetics, and integrate this new chemistry with strain-promoted azide-alkyne cycloaddition chemistry to enable heterovalent click reactions on NANPs. We applied these chemistries to formulate a prototypical chemical countermeasure against chemical nerve agents. We envision this additional chemistry finding broad utility in the synthetic toolkit accessible to the nucleic acid nanotechnology community.

Geranylgeranylation is a critical post-translational modification essential for various cellular functions. However, current methods for synthesizing geranylgeranylated proteins are complex and costly, which hinders access to these proteins for both biophysical and biomaterials applications. Here, we present a method for the one-pot production of geranylgeranylated proteins in Escherichia coli. We engineered E. coli to express geranylgeranyl pyrophosphate synthase (GGS), an enzyme that catalyzes the production of geranylgeranyl pyrophosphate. By coexpressing GGS with a geranylgeranyltransferase, we achieved efficient geranylgeranylation of model protein substrates, including intrinsically disordered elastin-like polypeptides (ELPs) and globular proteins such as mCherry and the small GTPases RhoA and Rap1B. We examined the biophysical behavior of the resulting geranylgeranylated proteins and observed that this modification affects the phase-separation and nanoassembly of ELPs and lipid bilayer engagement of mCherry. Taken together, our method offers a scalable, versatile, and cost-effective strategy for producing geranylgeranylated proteins, paving the way for advances in biochemical research, therapeutic development, and biomaterial engineering.

Lysosome-targeting chimeras (LYTACs) harness the cell's lysosomal degradation machinery to break down extracellular and membrane proteins. Previous methods used a synthetic glycopeptide containing multiple serine-O-mannose-6-phosphate (poly-M6Pn), which presented challenges such as synthetic complexity and potential immunogenicity associated with poly-M6Pn. This study introduced a LYTAC formulation, LYTAC^gyM6pG, which uses glyco-engineered yeast-derived mannose-6-phosphate glycans (gyM6pGs) for lysosomal transport, overcoming synthetic complexities and immunogenic risks. The gyM6pGs used in LYTAC^gyM6pG are human-compatible (identical to the structures found in humans) and are efficiently produced through yeast fermentation, followed by the preparation of cell wall glycans and their in vitro modifications. We employed copper-free click chemistry (azide and dibenzocyclooctyne reactions) for the robust conjugation of gyM6pGs to a nanobody targeting the immune checkpoint protein PD-L1, thereby streamlining the assembly of LYTAC^gyM6pG. We demonstrated that LYTAC^gyM6pG effectively degraded endogenous and recombinant PD-L1 proteins on the cell surface by directing them to the lysosome via the cation-independent mannose-6-phosphate receptor pathway. Furthermore, LYTAC^gyM6pG significantly enhanced T cell-mediated cytotoxicity against cancer cells, surpassing the efficacy of nanobodies alone. The successful application of gyM6pGs in the development of LYTAC^gyM6pG highlights the potential for a more viable and scalable therapeutic production of LYTACs, paving the way for broader therapeutic applications, including cancer treatment.

This study explores the use of lateral flow assays (LFAs), recognized for their simplicity and ease-of-use, as a tool for characterizing nanoparticles functionalized with various biomolecules (e.g., proteins, antibodies, and nucleic acids). A half-strip model system was developed using ovalbumin (OVA) conjugated to gold nanoparticles (AuNPs). The characterization results obtained with LFAs were compared to those from traditional methods such as infrared spectroscopy and fluorescence labeling. The advantages of LFAs in characterizing such conjugated nanosystems were clearly demonstrated. The use of half-strip assays could not only confirm the presence of OVA on AuNPs but also enable the quantification of OVA bound per nanoparticle, offering a rapid and quantitative characterization method. Additionally, the assay showcased its versatility, as it was successfully applied to optimize the covalent coupling conditions of OVA on AuNPs, as well as to differentiate between covalently bound and adsorbed proteins. Furthermore, LFAs were employed to detect antibodies on functionalized nanoparticles, optimize their coupling to a newly developed organic coating, and confirm both the grafting of nucleic acids onto the surface and their pairing with complementary strands. These findings underscore the remarkable adaptability of LFAs for characterizing diverse nanoconjugates. Overall, LFAs stand out as a versatile and accessible tool for characterizing complex bioconjugated nanosystems, making them highly suitable for rapid Quality Control (QC) analysis and bioconjugation optimization.

Glioblastoma (GBM) is a highly invasive tumor with poorly defined boundaries, often leaving residual tissue after surgery, which contributes to the recurrence and poor prognosis. A critical challenge in GBM treatment is the precise identification of tumor boundaries during surgery to achieve a safe and complete resection. In this study, we present a novel near-infrared fluorescent agent, IR-PEG-cRGD, that is designed to accurately delineate GBM boundaries for surgical navigation of tumor resection. IR-PEG-cRGD is successfully prepared from the cyanine dye IR-820, which is conjugated to poly(ethylene glycol) (PEG) to prolong circulation time and enhance tumor accumulation. Additionally, a glioma-targeting peptide (cRGD, cyclo(Arg-Gly-Asp-d-Phe-Cys)) is conjugated to PEG to selectively target GBM. IR-PEG-cRGD demonstrates effective targeting and enrichment in subcutaneous human-derived GBM mice models, enabling specific distinguishing of the GBM margin from the surrounding parenchyma with a high signal-to-background ratio (SBR) of 4.79. Moreover, IR-PEG-cRGD can pass across the blood-brain barrier (BBB) efficiently. These findings indicate that IR-PEG-cRGD can serve as a valuable tool for the precise intraoperative delineation of GBM boundaries, aiding in safe and complete tumor resection.

Historically, RNA delivery via nanoparticles has primarily relied on encapsulation, as demonstrated by lipid nanoparticles in SARS-CoV-2 vaccines. Concerns about RNA degradation on nanoparticle surfaces initially limited the exploration of adsorption-based approaches. However, recent advancements have renewed interest in adsorption as a viable alternative. This Viewpoint explores the approaches of RNA incorporation in nanoparticles, comparing encapsulation, adsorption, and the combination of encapsulation and adsorption, and presents a framework to guide the selection of the most suitable strategy based on general characteristics.

We report the chemical conjugation of a recombinant Adeno Associated Virus (rAAV) capsid with various functionalities, including proteins, using a bioorthogonal strategy. rAAVs were azido-coated or dibenzylcyclooctyne (DBCO)-coated by chemically modifying lysine or tyrosine residues. Lysine residues were modified using a phenyl isothiocyanate anchor, and tyrosine residues using either an aryl diazonium salt or a N-methyl luminol derivative. We demonstrate anchor-dependent labeling levels, as observed with biochemical assays and mass spectrometry. Strain-promoted azide-alkyne cycloaddition (SPAAC) was then implemented and evaluated on the rAAV to append functionalities such as fluorescein, biotin, and carbohydrates to the azido-coated capsids. We confirmed the efficiency of the bioorthogonal reaction and observed a stronger reactivity with dibenzylcyclooctyne (DBCO) compared to bicyclononyne (BCN). The optimized SPAAC reaction was finally used to label the viral vectors with two relevant nanobodies targeting specific immune cell receptors (CD62L and CD45). In vitro transduction assays conducted with one rAAV-nanobody conjugate demonstrated the promising targeting properties of these chemically modified vectors. Thus, we anticipate that this strategy will positively impact the field of rAAV capsid engineering and contribute in tissue-specific targeting for the optimization of gene therapy treatments.

Enveloped nanoparticles such as extracellular vesicles (EVs) and virus-like particles (VLPs) have emerged as promising nanocarriers capable of transporting bioactive molecules for drug delivery and vaccination. Optimized functionalization methodologies are required to increase the functionalization levels of these nanoparticles, enhancing their performance. Here, a bioorthogonal copper-free strain-promoted azide-alkyne cycloaddition (SPAAC) reaction has been optimized to functionalize human immunodeficiency virus type 1 (HIV-1) Gag-based VLPs and EVs. The optimization process has been carried out through reaction kinetics and design of experiments (DoE) using Cy5 as a reporter molecule. The functionalization of both VLPs and EVs has been studied using super-resolution fluorescence microscopy (SRFM), revealing remarkable differences between Gag-VLPs and coproduced EVs. EVs produced by mock transfection and cell growth have been functionalized achieving a mean of 3618.63 ± 48.91 and 6498.75 ± 352.71 Cy5 molecules covalently linked per particle (Cy5_cov/particle), respectively. Different nanoparticles have been functionalized with two linear B-cell epitopes from the Spike protein of SARS-CoV-2, S_315-338 TSNFRVQPTESIVRFPNITNLCPF and S_648-663 GCLIGAEHVNNSYECD, and analyzed by an immunoassay with sera from COVID-19 patients. The obtained results validate the selected B-cell epitopes and highlight the potential of the optimized functionalization approach for the development of nanoparticle-based vaccines.

Lysosomal enzyme replacement therapy (ERT) holds potential for treating lysosomal storage disorders, but achieving targeted delivery of deficient therapeutic enzymes remains a significant challenge. This study presents a novel approach for the lysosome-specific delivery of the β-glucosidase (B8CYA8) enzyme by covalently conjugating lysosome-targeting mannose-6-phosphate functionalized glycopolypeptides (M6P-GP). We used a protein-glycopolypeptide conjugate developed through advanced protein engineering and bioconjugation techniques. By conjugating β-glucosidase to M6P-GP that has a high affinity for the cation-independent mannose-6-phosphate receptors (CI-MPR) and lysosomal receptors, we enhance the enzyme's selective intracellular uptake and lysosome-specific localization. To attain maximum activity of the near-native enzyme after delivery, we have designed and synthesized an acetal linkage containing the pH-responsive linker maleimide-acetal-azide (MAA), which will cleave in the lysosomal acidic pH to detach the glycopolypeptide from the protein backbone. We demonstrated the efficient cellular uptake of the protein-glycopolypeptide conjugate and showed targeted lysosome delivery, leading to increased enzymatic activity compared to untreated cells. Our results proved that the approach mainly improves the specificity and efficiency of enzyme delivery, particularly into lysosomes, which may enable new methods for ERT. These findings suggest that protein-glycopolypeptide conjugates could represent a class of bioconjugates to design targeted enzyme therapies, offering a pathway to the effective treatment of Gaucher disease (GD) and potentially other related lysosomal storage disorders.