Publications by authors named "Chun-Long Chen"

R-loops or DNA-RNA hybrids are prominent nucleic acid structures that commonly arise during transcription. These structures play important biological functions, such as regulating gene expression and DNA repair. However, when unresolved by nucleic acid processing factors, pathological R-loops can be harmful and lead to genome instability.

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Carbonic anhydrase (CA) mimics have received significant attention due to their promising applications in the enhanced hydration and sequestration of CO. Herein, we report the assembly of sequence-defined peptoids into crystalline nanomaterials with controlled microenvironment of active sites as CA mimics for promoted hydration and sequestration of CO. By incorporating specific ligands into self-assembling peptoids and coordinating these ligands with metal cations, we synthesize a variety of crystalline nanosheets and nanotubes as efficient CA mimics comparable to natural bovine CA.

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N-Heterocyclic carbene (NHC) ligands, with strong metal-binding affinity, offer a robust platform for constructing organic-inorganic nanohybrids with high stability and tunable properties. However, achieving precise structural control in a simple manner remains challenging. Here, we report a one-pot synthesis of nanohybrids using self-assembling peptoids functionalized with histidine-2-ylidene, which simultaneously enable peptoid assembly and NHC-metal binding.

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While natural enzymes excel at catalysis and sensing, they often suffer from high cost and low stability in applications outside living systems. Among tremendous efforts made toward the design and synthesis of catalytic biomimetic materials, the approach of using crystalline nanomaterials assembled from sequence-defined polymers has emerged as a promising strategy. Herein, we report the assembly of metalloporphyrin peptoids into crystalline nanomaterials as a multifunctional system for biomimetic catalysis and sensing.

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Recently, Suwayyid and Wei introduced commutative algebra as an emerging paradigm for machine learning and data science. In this work, we propose commutative algebra machine learning (CAML) for the prediction of protein-ligand binding affinities. Specifically, we apply persistent Stanley-Reisner theory, a key concept in combinatorial commutative algebra, to the affinity predictions of protein-ligand binding and metalloprotein-ligand binding.

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Metal-organic frameworks (MOFs) are porous, crystalline materials with high surface area, adjustable porosity, and structural tunability, making them ideal for diverse applications. However, traditional experimental and computational methods have limited scalability and interpretability, hindering effective exploration of MOF structure-property relationships. To address these challenges, we introduce, for the first time, a category-specific topological learning (CSTL), which combines algebraic topology with chemical insights for robust property prediction.

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Combining the advantages of structural programmability in sequence-defined biomimetic molecules and the controllable packing geometry in nanoparticle superlattices, we demonstrate a self-assembled organic-inorganic superlattice whose structure can be altered with the slightest change in the sequence of the organic counterpart. Here, oleate-coated CdS quantum dots (QDs) form a square-packed superlattice with a 1:1 molar equivalence of a diblock amphiphilic peptoid (NbrpeDig) in chloroform. In contrast, no apparent structure is observed in the organic solvent alone.

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Genomic heterogeneity has largely been overlooked in single-cell replication timing (scRT) studies. Here, we develop MnM, an efficient machine learning-based tool that allows disentangling scRT profiles from heterogenous samples. We use single-cell copy number data to accurately perform missing value imputation, identify cell replication states, and detect genomic heterogeneity.

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Metal-organic frameworks (MOFs) are porous, crystalline materials with high surface area, adjustable porosity, and structural tunability, making them ideal for diverse applications. However, traditional experimental and computational methods have limited scalability and interpretability, hindering effective exploration of MOF structure-property relationships. To address these challenges, we introduce, for the first time, a category-specific topological learning (CSTL), which combines algebraic topology with chemical insights for robust property prediction.

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Background: The unmet needs of managing patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer who progress after cyclin-dependent kinase (CDK)4/6 inhibitor (CDK4/6i) treatment remain unclarified.

Methods: This was a phase 1b/2, single-arm, open-label study that enrolled 29 patients with HR+/HER2- breast cancer who experienced first-line palbociclib treatment failure. The primary endpoint was the incidence of dose-limiting toxicity (DLT).

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The extensive deposits of calcium carbonate (CaCO) generated by marine organisms constitute the largest and oldest carbon dioxide (CO) reservoir. These organisms utilize macromolecules like peptides and proteins to facilitate the nucleation and growth of carbonate minerals, serving as an effective method for CO sequestration. However, the precise mechanisms behind this process remain elusive.

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Article Synopsis
  • Silica-organic composites are being explored for their eco-friendly properties and unique interactions between macromolecules and aqueous silica, which enhance the physical traits of living systems.
  • The review discusses silicification in organisms and how various biomacromolecules may affect these processes, but notes that current research often lacks consistency and clarity.
  • Advances in biopolymer chemistry open new pathways to study the chemistry of functional groups within macromolecules, potentially leading to innovative biocomposite applications in fields like medicine and clean energy.
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  • Bacterial infections have historically posed significant threats, leading to research on natural antimicrobial peptides (AMPs) and their synthetic alternatives due to AMPs' limitations like degradation and low effectiveness.
  • By using self-assembly and pore-forming capabilities of peptoids, researchers developed a new class of low-molecular weight peptoid antibiotics that are effective against various drug-resistant bacteria such as MRSA and VREF.
  • Studies reveal that these peptoids disrupt bacterial membranes to kill both Gram-positive and Gram-negative bacteria, offering a promising approach to tackle growing drug resistance.
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Hierarchical self-assembly represents a powerful strategy for the fabrication of functional materials across various length scales. However, achieving precise formation of functional hierarchical assemblies remains a significant challenge and requires a profound understanding of molecular assembly interactions. In this study, we present a molecular-level understanding of the hierarchical assembly of sequence-defined peptoids into multidimensional functional materials, including twisted nanotube bundles serving as a highly efficient artificial light harvesting system.

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A long-standing challenge in bioinspired materials is to design and synthesize synthetic materials that mimic the sophisticated structures and functions of natural biomaterials, such as helical protein assemblies that are important in biological systems. Herein, we report the formation of a series of nanohelices from a type of well-developed protein-mimetics called peptoids. We demonstrate that nanohelix structures and supramolecular chirality can be well-controlled through the side-chain chemistry.

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The design, synthesis, and fabrication of functional nanomaterials with specific properties remain a long-standing goal for many scientific fields. The self-assembly of sequence-defined biomimetic synthetic polymers presents a fundamental strategy to explore the chemical space beyond biological systems to create advanced nanomaterials. Moreover, subsequent chemical modification of existing nanostructures is a unique approach for accessing increasingly complex nanostructures and introducing functionalities.

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Article Synopsis
  • Two-dimensional (2D) materials, especially peptoids, have gained attention for their diverse applications from chemical sensing to biomedicine due to their unique properties like high stability and self-repair.
  • This study examined how different peptoid sequences affect their self-assembly into 2D crystalline sheets using techniques like Atomic Force Microscopy (AFM) and X-ray scattering.
  • Results indicated that peptoids with specific structural characteristics influence their growth behavior on surfaces, revealing variations in assembly rates and stability based on sequence composition and hydrophobic interactions.
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Biomolecules modulate inorganic crystallization to generate hierarchically structured biominerals, but the atomic structure of the organic-inorganic interfaces that regulate mineralization remain largely unknown. We hypothesized that heterogeneous nucleation of calcium carbonate could be achieved by a structured flat molecular template that pre-organizes calcium ions on its surface. To test this hypothesis, we design helical repeat proteins (DHRs) displaying regularly spaced carboxylate arrays on their surfaces and find that both protein monomers and protein-Ca supramolecular assemblies directly nucleate nano-calcite with non-natural {110} or {202} faces while vaterite, which forms first in the absence of the proteins, is bypassed.

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Maintaining chromatin integrity at the repetitive non-coding DNA sequences underlying centromeres is crucial to prevent replicative stress, DNA breaks and genomic instability. The concerted action of transcriptional repressors, chromatin remodelling complexes and epigenetic factors controls transcription and chromatin structure in these regions. The histone chaperone complex ATRX/DAXX is involved in the establishment and maintenance of centromeric chromatin through the deposition of the histone variant H3.

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Achieving predictable biomimetic crystallization using sequence-defined synthetic molecules in mild conditions represents a long-standing challenge in materials synthesis. Herein we report a peptoid-based approach for biomimetic control over the formation of nanostructured ZnO materials in ambient aqueous conditions. A series of two-dimensional (2D) ZnO nanomaterials have been successfully obtained using amphiphilic peptoids with different numbers, ratios, and patterns of various hydrophilic and hydrophobic side chains.

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The detoxification of lethal organophosphate (OP) residues in the environment is crucial to prevent human exposure and protect modern society. Despite serving as excellent catalysts for OP degradation, natural enzymes require costly preparation and readily deactivate upon exposure to environmental conditions. Herein, we designed and prepared a series of phosphotriesterase mimics based on stable, self-assembled peptoid membranes to overcome these limitations of the enzymes and effectively catalyze the hydrolysis of dimethyl -nitrophenyl phosphate (DMNP)─a nerve agent simulant.

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Peptoids are a class of highly customizable biomimetic foldamers that retain properties from both proteins and polymers. It has been shown that peptoids can adopt peptide-like secondary structures through the careful selection of sidechain chemistries, but the underlying conformational landscapes that drive these assemblies at the molecular level remain poorly understood. Given the high flexibility of the peptoid backbone, it is essential that methods applied to study peptoid secondary structure formation possess the requisite sensitivity to discriminate between structurally similar yet energetically distinct microstates.

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Peptoids (N-substituted glycines) are a group of highly controllable peptidomimetic polymers. Amphiphilic diblock peptoids have been engineered to assemble crystalline nanospheres, nanofibrils, nanosheets, and nanotubes with biochemical, biomedical, and bioengineering applications. The mechanical properties of peptoid nanoaggregates and their relationship to the emergent self-assembled morphologies have been relatively unexplored and are critical for the rational design of peptoid nanomaterials.

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