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1.
Acta Crystallogr D Struct Biol ; 80(Pt 5): 314-327, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38700059

RESUMO

Radiation damage remains one of the major impediments to accurate structure solution in macromolecular crystallography. The artefacts of radiation damage can manifest as structural changes that result in incorrect biological interpretations being drawn from a model, they can reduce the resolution to which data can be collected and they can even prevent structure solution entirely. In this article, we discuss how to identify and mitigate against the effects of radiation damage at each stage in the macromolecular crystal structure-solution pipeline.


Assuntos
Substâncias Macromoleculares , Cristalografia por Raios X/métodos , Substâncias Macromoleculares/química , Modelos Moleculares , Proteínas/química
2.
Anal Chim Acta ; 1306: 342609, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38692788

RESUMO

BACKGROUND: Accurate quantitative analysis of small molecule metabolites in biological samples is of great significance. Hydroxypolycyclic aromatic hydrocarbons (OH-PAHs) are metabolic derivatives of emerging pollutants, reflecting exposure to polycyclic aromatic hydrocarbons (PAHs). Macromolecules such as proteins and enzymes in biological samples will interfere with the accurate quantification of OH-PAHs, making direct analysis impossible, requiring a series of complex treatments such as enzymatic hydrolysis. Therefore, the development of matrix-compatible fiber coatings that can exclude macromolecules is of great significance to improve the ability of solid-phase microextraction (SPME) technology to selectively quantify small molecules in complex matrices and achieve rapid and direct analysis. RESULTS: We have developed an innovative coating with a stable macromolecular barrier using electrospinning and flexible filament winding (FW) technologies. This coating, referred to as the hollow fibrous covalent organic framework@polyionic liquid (F-COF@polyILs), demonstrates outstanding conductivity and stability. It accelerates the adsorption equilibrium time (25 min) for polar OH-PAHs through electrically enhanced solid-phase microextraction (EE-SPME) technology. Compared to the powder form, F-COF@polyILs coating displays effective non-selective large-size molecular sieving. Combining gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS), we have established a simple, efficient quantitative analysis method for OH-PAHs with a low detection limit (0.008-0.05 ng L-1), wide linear range (0.02-1000 ng L-1), and good repeatability (1.0%-7.3 %). Experimental results show that the coated fiber exhibits good resistance to matrix interference (2.5%-16.7 %) in complex biological matrices, and has been successfully used for OH-PAHs analysis in human urine and plasma. SIGNIFICANCE: FW technology realizes the transformation of the traditional powder form of COF in SPME coating to a uniform non-powder coating, giving its ability to exclude large molecules in complex biological matrices. A method for quantitatively detecting OH-PAHs in real biological samples was also developed. Therefore, the filament winding preparation method for F-COF@polyILs coated fibers, along with fibrous COFs' morphology control, has substantial implications for efficiently extracting target compounds from complex matrices.


Assuntos
Microextração em Fase Sólida , Microextração em Fase Sólida/métodos , Estruturas Metalorgânicas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Substâncias Macromoleculares/química , Limite de Detecção , Adsorção , Técnicas Eletroquímicas/métodos
3.
Adv Immunol ; 161: 17-51, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38763701

RESUMO

The innate immune system uses a distinct set of germline-encoded pattern recognition receptors to recognize molecular patterns initially thought to be unique to microbial invaders, named pathogen-associated molecular patterns. The concept was later further developed to include similar molecular patterns originating from host cells during tissue damage, known as damage-associated molecular patterns. However, recent advances in the mechanism of monogenic inflammatory diseases have highlighted a much more expansive repertoire of cellular functions that are monitored by innate immunity. Here, we summarize several examples in which an innate immune response is triggered when homeostasis of macromolecule in the cell is disrupted in non-infectious or sterile settings. These ever-growing sensing mechanisms expand the repertoire of innate immune recognition, positioning it not only as a key player in host defense but also as a gatekeeper of cellular homeostasis. Therapeutics inspired by these advances to restore cellular homeostasis and correct the immune system could have far-reaching implications.


Assuntos
Homeostase , Imunidade Inata , Receptores de Reconhecimento de Padrão , Humanos , Animais , Receptores de Reconhecimento de Padrão/metabolismo , Substâncias Macromoleculares/metabolismo , Moléculas com Motivos Associados a Patógenos/imunologia , Moléculas com Motivos Associados a Patógenos/metabolismo , Transdução de Sinais , Inflamação/imunologia
4.
Nat Commun ; 15(1): 4403, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38782907

RESUMO

Controlled manipulation of cultured cells by delivery of exogenous macromolecules is a cornerstone of experimental biology. Here we describe a platform that uses nanopipettes to deliver defined numbers of macromolecules into cultured cell lines and primary cells at single molecule resolution. In the nanoinjection platform, the nanopipette is used as both a scanning ion conductance microscope (SICM) probe and an injection probe. The SICM is used to position the nanopipette above the cell surface before the nanopipette is inserted into the cell into a defined location and to a predefined depth. We demonstrate that the nanoinjection platform enables the quantitative delivery of DNA, globular proteins, and protein fibrils into cells with single molecule resolution and that delivery results in a phenotypic change in the cell that depends on the identity of the molecules introduced. Using experiments and computational modeling, we also show that macromolecular crowding in the cell increases the signal-to-noise ratio for the detection of translocation events, thus the cell itself enhances the detection of the molecules delivered.


Assuntos
DNA , Imagem Individual de Molécula , Humanos , Imagem Individual de Molécula/métodos , DNA/metabolismo , DNA/química , Animais , Nanotecnologia/métodos , Proteínas/metabolismo , Proteínas/química , Substâncias Macromoleculares/metabolismo , Substâncias Macromoleculares/química , Razão Sinal-Ruído
5.
Proc Natl Acad Sci U S A ; 121(19): e2403384121, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38691585

RESUMO

Macromolecular complexes are often composed of diverse subunits. The self-assembly of these subunits is inherently nonequilibrium and must avoid kinetic traps to achieve high yield over feasible timescales. We show how the kinetics of self-assembly benefits from diversity in subunits because it generates an expansive parameter space that naturally improves the "expressivity" of self-assembly, much like a deeper neural network. By using automatic differentiation algorithms commonly used in deep learning, we searched the parameter spaces of mass-action kinetic models to identify classes of kinetic protocols that mimic biological solutions for productive self-assembly. Our results reveal how high-yield complexes that easily become kinetically trapped in incomplete intermediates can instead be steered by internal design of rate-constants or external and active control of subunits to efficiently assemble. Internal design of a hierarchy of subunit binding rates generates self-assembly that can robustly avoid kinetic traps for all concentrations and energetics, but it places strict constraints on selection of relative rates. External control via subunit titration is more versatile, avoiding kinetic traps for any system without requiring molecular engineering of binding rates, albeit less efficiently and robustly. We derive theoretical expressions for the timescales of kinetic traps, and we demonstrate our optimization method applies not just for design but inference, extracting intersubunit binding rates from observations of yield-vs.-time for a heterotetramer. Overall, we identify optimal kinetic protocols for self-assembly as a powerful mechanism to achieve efficient and high-yield assembly in synthetic systems whether robustness or ease of "designability" is preferred.


Assuntos
Algoritmos , Cinética , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo
6.
Int J Mol Sci ; 25(10)2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38791335

RESUMO

Macromolecules exhibit ordered structures and complex functions in an aqueous environment with strong thermodynamic fluctuations [...].


Assuntos
Substâncias Macromoleculares , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Termodinâmica , Humanos
7.
J Am Chem Soc ; 146(21): 14844-14855, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38747446

RESUMO

Nature employs sophisticated mechanisms to precisely regulate self-assembly and functions within biological systems, exemplified by the formation of cytoskeletal filaments. Various enzymatic reactions and auxiliary proteins couple with the self-assembly process, meticulously regulating the length and functions of resulting macromolecular structures. In this context, we present a bioinspired, reaction-coupled approach for the controlled supramolecular polymerization in synthetic systems. To achieve this, we employ an enzymatic reaction that interfaces with the adenosine triphosphate (ATP)-templated supramolecular polymerization of naphthalene diimide monomers (NSG). Notably, the enzymatic production of ATP (template) plays a pivotal role in facilitating reaction-controlled, cooperative growth of the NSG monomers. This growth process, in turn, provides positive feedback to the enzymatic production of ATP, creating an ideal reaction-coupled assembly process. The success of this approach is further evident in the living-growth characteristic observed during seeding experiments, marking this method as the pioneering instance where reaction-coupled self-assembly precisely controls the growth kinetics and structural aspects of supramolecular polymers in a predictive manner, akin to biological systems.


Assuntos
Trifosfato de Adenosina , Imidas , Naftalenos , Polimerização , Naftalenos/química , Naftalenos/metabolismo , Naftalenos/síntese química , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/química , Imidas/química , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Substâncias Macromoleculares/síntese química , Estrutura Molecular , Cinética , Polímeros/química
8.
Int J Biol Macromol ; 269(Pt 1): 132001, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38702007

RESUMO

Plant-derived bioactive macromolecules (i.e., proteins, lipids, and nucleic acids) were prepared as extracellular vesicles (EVs). Plant-derived EVs are gaining pharmaceutical research interest because of their bioactive components and delivery properties. The spherical nanosized EVs derived from Raphanus sativus L. var. caudatus Alef microgreens previously showed antiproliferative activity in HCT116 colon cancer cells from macromolecular compositions (predominantly proteins). To understand the mechanism of action, the biological activity studies, i.e., antiproliferation, cellular biochemical changes, DNA conformational changes, DNA damage, apoptotic nuclear morphological changes, apoptosis induction, and apoptotic pathways, were determined by neutral red uptake assay, synchrotron radiation-based Fourier transform infrared microspectroscopy, circular dichroism spectroscopy, comet assay, 4',6-diamidino-2-phenylindole (DAPI) staining, flow cytometry, and caspase activity assay, respectively. EVs inhibited HCT116 cell growth in concentration- and time-dependent manners, with a half-maximal inhibitory concentration of 675.4 ± 33.8 µg/ml at 48 h and a selectivity index of 1.5 ± 0.076. HCT116 treated with EVs mainly changed the cellular biochemical compositions in the nucleic acids and carbohydrates region. The DNA damage caused no changes in DNA conformation. The apoptotic nuclear morphological changes were associated with the increased apoptotic cell population. The apoptotic cell death was induced by both extrinsic and intrinsic pathways. EVs have potential as antiproliferative bioparticles.


Assuntos
Apoptose , Proliferação de Células , Dano ao DNA , Vesículas Extracelulares , Raphanus , Humanos , Apoptose/efeitos dos fármacos , Raphanus/química , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/química , Células HCT116 , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/patologia , Neoplasias do Colo/metabolismo , Estrutura Secundária de Proteína , Substâncias Macromoleculares/química , Substâncias Macromoleculares/farmacologia
9.
Int J Biol Macromol ; 269(Pt 1): 132079, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38705338

RESUMO

The global issue of pollution caused by the misuse and indiscriminate application of pesticides has reached critical levels. In this vein, encapsulating pesticides with carriers offers a promising approach that impacts key parameters such as pesticide release kinetics, stability, and biocompatibility, enhancing the safe and effective delivery of agrochemicals. Encapsulated pesticides hold the potential to reduce off-target effects, decrease environmental contamination, and improve overall crop protection. This review highlights the potential benefits and challenges associated with the use of both organic and in-organic carriers in pesticide encapsulation, and the current state of research in this field. Overall, the encapsulation of pesticides with carriers presents a promising approach for the safe and effective delivery of these vital agricultural compounds. By harnessing the advantages of encapsulation, this technique offers a potential solution to mitigate the adverse effects of conventional pesticides and contribute towards sustainable and environmentally conscious farming practices. Further research and development in this field is necessary to optimize the encapsulation process, carrier properties and advance towards sustainable and environmentally friendly pesticide delivery systems.


Assuntos
Portadores de Fármacos , Praguicidas , Praguicidas/química , Portadores de Fármacos/química , Substâncias Macromoleculares/química , Humanos
10.
Int J Biol Macromol ; 268(Pt 2): 131874, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38692547

RESUMO

Serious orthopedic disorders resulting from myriad diseases and impairments continue to pose a considerable challenge to contemporary clinical care. Owing to its limited regenerative capacity, achieving complete bone tissue regeneration and complete functional restoration has proven challenging with existing treatments. By virtue of cellular regenerative and paracrine pathways, stem cells are extensively utilized in the restoration and regeneration of bone tissue; however, low survival and retention after transplantation severely limit their therapeutic effect. Meanwhile, biomolecule materials provide a delivery platform that improves stem cell survival, increases retention, and enhances therapeutic efficacy. In this review, we present the basic concepts of stem cells and extracellular vesicles from different sources, emphasizing the importance of using appropriate expansion methods and modification strategies. We then review different types of biomolecule materials, focusing on their design strategies. Moreover, we summarize several forms of biomaterial preparation and application strategies as well as current research on biomacromolecule materials loaded with stem cells and extracellular vesicles. Finally, we present the challenges currently impeding their clinical application for the treatment of orthopedic diseases. The article aims to provide researchers with new insights for subsequent investigations.


Assuntos
Vesículas Extracelulares , Células-Tronco , Vesículas Extracelulares/química , Humanos , Células-Tronco/citologia , Animais , Materiais Biocompatíveis/química , Doenças Ósseas/terapia , Regeneração Óssea , Transplante de Células-Tronco/métodos , Substâncias Macromoleculares/química , Substâncias Macromoleculares/farmacologia
11.
Nature ; 628(8006): 47-56, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38570716

RESUMO

Most life scientists would agree that understanding how cellular processes work requires structural knowledge about the macromolecules involved. For example, deciphering the double-helical nature of DNA revealed essential aspects of how genetic information is stored, copied and repaired. Yet, being reductionist in nature, structural biology requires the purification of large amounts of macromolecules, often trimmed off larger functional units. The advent of cryogenic electron microscopy (cryo-EM) greatly facilitated the study of large, functional complexes and generally of samples that are hard to express, purify and/or crystallize. Nevertheless, cryo-EM still requires purification and thus visualization outside of the natural context in which macromolecules operate and coexist. Conversely, cell biologists have been imaging cells using a number of fast-evolving techniques that keep expanding their spatial and temporal reach, but always far from the resolution at which chemistry can be understood. Thus, structural and cell biology provide complementary, yet unconnected visions of the inner workings of cells. Here we discuss how the interplay between cryo-EM and cryo-electron tomography, as a connecting bridge to visualize macromolecules in situ, holds great promise to create comprehensive structural depictions of macromolecules as they interact in complex mixtures or, ultimately, inside the cell itself.


Assuntos
Biologia Celular , Células , Microscopia Crioeletrônica , Tomografia com Microscopia Eletrônica , Microscopia Crioeletrônica/métodos , Microscopia Crioeletrônica/tendências , Tomografia com Microscopia Eletrônica/métodos , Tomografia com Microscopia Eletrônica/tendências , Substâncias Macromoleculares/análise , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Substâncias Macromoleculares/ultraestrutura , Biologia Celular/instrumentação , Células/química , Células/citologia , Células/metabolismo , Células/ultraestrutura , Humanos
12.
Food Res Int ; 184: 114247, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38609226

RESUMO

Konjac glucomannan (KGM) can significantly prolong gastrointestinal digestion. However, it is still worth investigating whether the macromolecular crowding (MMC) induced by KGM is correlated with digestion. In this paper, the MMC effect was quantified by fluorescence resonance energy transfer and microrheology, and the digests of starch, protein, and oil were determined. The digestive enzymes were analyzed by enzyme reaction kinetic and fluorescence quenching. The results showed that higher molecular weight (604.85 âˆ¼ 1002.21 kDa) KGM created a larger MMC (>0.8), and influenced the digestion of macronutrients; the digests of starch, protein, and oil all decreased significantly. MMC induced by KGM decreased the Michaelis-Menten constants (Km and Vmax) of pancreatic α-amylase (PPA), pepsin (PEP), and pancreatic lipase (PPL). The larger MMC (>0.8) induced by KGM resulted in the decrease of fluorescence quenching constants (Ksv) in PPA and PPL, and the increase of Ksv in PEP. Therefore, varying degrees of MMC induced by KGM could play a role in regulating digestion and the inhibitory effect on digestion was more significant in a relatively more crowded environment induced by KGM. This study provides theoretical support for the strategies of nutrient digestion regulation from the perspective of MMC caused by dietary fiber.


Assuntos
Mananas , Pepsina A , Espectrometria de Fluorescência , Substâncias Macromoleculares , alfa-Amilases Pancreáticas , Amido
13.
Nat Commun ; 15(1): 3413, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38649740

RESUMO

The functions of biomolecular condensates are thought to be influenced by their material properties, and these will be determined by the internal organization of molecules within condensates. However, structural characterizations of condensates are challenging, and rarely reported. Here, we deploy a combination of small angle neutron scattering, fluorescence recovery after photobleaching, and coarse-grained molecular dynamics simulations to provide structural descriptions of model condensates that are formed by macromolecules from nucleolar granular components (GCs). We show that these minimal facsimiles of GCs form condensates that are network fluids featuring spatial inhomogeneities across different length scales that reflect the contributions of distinct protein and peptide domains. The network-like inhomogeneous organization is characterized by a coexistence of liquid- and gas-like macromolecular densities that engenders bimodality of internal molecular dynamics. These insights suggest that condensates formed by multivalent proteins share features with network fluids formed by systems such as patchy or hairy colloids.


Assuntos
Condensados Biomoleculares , Simulação de Dinâmica Molecular , Espalhamento a Baixo Ângulo , Condensados Biomoleculares/química , Recuperação de Fluorescência Após Fotodegradação , Difração de Nêutrons , Substâncias Macromoleculares/química , Proteínas/química
14.
Int J Biol Macromol ; 267(Pt 2): 131411, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38588841

RESUMO

Skeletal muscle (SM) mass and strength maintenance are important requirements for human well-being. SM regeneration to repair minor injuries depends upon the myogenic activities of muscle satellite (stem) cells. However, losses of regenerative properties following volumetric muscle loss or severe trauma or due to congenital muscular abnormalities are not self-restorable, and thus, these conditions have major healthcare implications and pose clinical challenges. In this context, tissue engineering based on different types of biomaterials and scaffolds provides an encouraging means of structural and functional SM reconstruction. In particular, biomimetic (able to transmit biological signals) and several porous scaffolds are rapidly evolving. Several biological macromolecules/biomaterials (collagen, gelatin, alginate, chitosan, and fibrin etc.) are being widely used for SM regeneration. However, available alternatives for SM regeneration must be redesigned to make them more user-friendly and economically feasible with longer shelf lives. This review aimed to explore the biological aspects of SM regeneration and the roles played by several biological macromolecules and scaffolds in SM regeneration in cases of volumetric muscle loss.


Assuntos
Materiais Biocompatíveis , Músculo Esquelético , Regeneração , Engenharia Tecidual , Alicerces Teciduais , Humanos , Alicerces Teciduais/química , Músculo Esquelético/fisiologia , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/química , Substâncias Macromoleculares/química
15.
Int J Biol Macromol ; 267(Pt 2): 131494, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38608974

RESUMO

Transcatheter arterial embolization (TACE) has been used in the treatment of malignant tumors, sudden hemorrhage, uterine fibroids, and other diseases, and with advances in imaging techniques and devices, materials science, and drug release technology, more and more embolic agents that are drug-carrying, self-imaging, or have multiple functions are being developed. Microspheres provide safer and more effective therapeutic results as embolic agents, with their unique spherical appearance and good embolic properties. Embolic microspheres are the key to arterial embolization, blocking blood flow and nutrient supply to the tumor target. This review summarizes some of the currently published embolic microspheres, classifies embolic microspheres according to matrix, and summarizes the characteristics of the microsphere materials, the current status of research, directions, and the value of existing and potential applications. It provides a direction to promote the development of embolic microspheres towards multifunctionalization, and provides a reference to promote the research and application of embolic microspheres in the treatment of tumors.


Assuntos
Embolização Terapêutica , Microesferas , Humanos , Embolização Terapêutica/métodos , Animais , Neoplasias/tratamento farmacológico , Neoplasias/terapia , Substâncias Macromoleculares/química , Portadores de Fármacos/química
16.
Int J Biol Macromol ; 267(Pt 2): 131581, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38615866

RESUMO

Using Escherichia coli as a model, this manuscript delves into the intricate interactions between dimethyl sulfoxide (DMSO) and membranes, cellular macromolecules, and the effects on various aspects of bacterial physiology. Given DMSO's wide-ranging use as a solvent in microbiology, we investigate the impacts of both non-growth inhibitory (1.0 % and 2.5 % v/v) and slightly growth-inhibitory (5.0 % v/v) concentrations of DMSO. The results demonstrate that DMSO causes alterations in bacterial membrane potential, influences the electrochemical characteristics of the cell surface, and exerts substantial effects on the composition and structure of cellular biomolecules. Genome-wide gene expression data from DMSO-treated E. coli was used to further investigate and bolster the results. The findings of this study provide valuable insights into the complex relationship between DMSO and biological systems, with potential implications in drug delivery and cellular manipulation. However, it is essential to exercise caution when utilizing DMSO to enhance the solubility and delivery of bioactive compounds, as even at low concentrations, DMSO exerts non-inert effects on cellular macromolecules and processes.


Assuntos
Membrana Celular , Dimetil Sulfóxido , Escherichia coli , Dimetil Sulfóxido/farmacologia , Dimetil Sulfóxido/química , Escherichia coli/efeitos dos fármacos , Membrana Celular/metabolismo , Membrana Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Substâncias Macromoleculares/farmacologia , Potenciais da Membrana/efeitos dos fármacos
17.
J Am Chem Soc ; 146(18): 12577-12586, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38683934

RESUMO

Dynamic supramolecular assemblies, driven by noncovalent interactions, pervade the biological realm. In the synthetic domain, their counterparts, supramolecular polymers, endowed with remarkable self-repair and adaptive traits, are often realized through bioinspired designs. Recently, controlled supramolecular polymerization strategies have emerged, drawing inspiration from protein self-assembly. A burgeoning area of research involves mimicking the liquid-liquid phase separation (LLPS) observed in proteins to create coacervate droplets and recognizing their significance in cellular organization and diverse functions. Herein, we introduce a novel perspective on synthetic coacervates, extending beyond their established role in synthetic biology as dynamic, membraneless phases to enable structural control in synthetic supramolecular polymers. Drawing parallels with the cooperative growth of amyloid fibrils through LLPS, we present metastable coacervate droplets as dormant monomer phases for controlled supramolecular polymerization. This is achieved via a π-conjugated monomer design that combines structural characteristics for both coacervation through its terminal ionic groups and one-dimensional growth via a π-conjugated core. This design leads to a unique temporal LLPS, resulting in a metastable coacervate phase, which subsequently undergoes one-dimensional growth via nucleation within the droplets. In-depth spectroscopic and microscopic characterization provides insights into the temporal evolution of disordered and ordered phases. Furthermore, to modulate the kinetics of liquid-to-solid transformation and to achieve precise control over the structural characteristics of the resulting supramolecular polymers, we invoke seeding in the droplets, showcasing living growth characteristics. Our work thus opens up new avenues in the exciting field of supramolecular polymerization, offering general design principles and controlled synthesis of precision self-assembled structures in confined environments.


Assuntos
Polimerização , Substâncias Macromoleculares/química , Substâncias Macromoleculares/síntese química , Polímeros/química , Polímeros/síntese química , Extração Líquido-Líquido/métodos , Estrutura Molecular , Separação de Fases
19.
Mol Cell ; 84(9): 1783-1801.e7, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38614097

RESUMO

Liquid-liquid phase separation (LLPS) of putative assembly scaffolds has been proposed to drive the biogenesis of membraneless compartments. LLPS scaffolds are usually identified through in vitro LLPS assays with single macromolecules (homotypic), but the predictive value of these assays remains poorly characterized. Here, we apply a strategy to evaluate the robustness of homotypic LLPS assays. When applied to the chromosomal passenger complex (CPC), which undergoes LLPS in vitro and localizes to centromeres to promote chromosome biorientation, LLPS propensity in vitro emerged as an unreliable predictor of subcellular localization. In vitro CPC LLPS in aqueous buffers was enhanced by commonly used crowding agents. Conversely, diluted cytomimetic media dissolved condensates of the CPC and of several other proteins. We also show that centromeres do not seem to nucleate LLPS, nor do they promote local, spatially restrained LLPS of the CPC. Our strategy can be adapted to purported LLPS scaffolds of other membraneless compartments.


Assuntos
Centrômero , Centrômero/metabolismo , Substâncias Macromoleculares/metabolismo , Substâncias Macromoleculares/química , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Humanos , Separação de Fases
20.
Sci Rep ; 14(1): 9369, 2024 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653774

RESUMO

Human pharmaceuticals represent a major challenge in natural environment. A better knowledge on their mechanisms of action and adverse effects on cellular pathways is fundamental to predict long-term consequences for marine wildlife. The FTIRI Imaging (FTIRI) spectroscopy represents a vibrational technique allowing to map specific areas of non-homogeneous biological samples, providing a unique biochemical and ultrastructural fingerprint of the tissue. In this study, FTIRI technique has been applied, for the first time, to characterize (i) the chemical building blocks of digestive glands of Mytilus galloprovincialis, (ii) alterations and (iii) resilience of macromolecular composition, after a 14-days exposure to 0.5 µg/L of carbamazepine (CBZ), valsartan (VAL) and their mixture, followed by a 14-days recovery period. Spectral features of mussels digestive glands provided insights on composition and topographical distribution of main groups of biological macromolecules, such as proteins, lipids, and glycosylated compounds. Pharmaceuticals caused an increase in the total amount of protein and a significant decrease of lipids levels. Changes in macromolecular features reflected the modulation of specific molecular and biochemical pathways thus supporting our knowledge on mechanisms of action of such emerging pollutants. Overall, the applied approach could represent an added value within integrated strategies for the effects-based evaluation of environmental contaminants.


Assuntos
Sistema Digestório , Mytilus , Poluentes Químicos da Água , Animais , Mytilus/efeitos dos fármacos , Mytilus/metabolismo , Poluentes Químicos da Água/toxicidade , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Substâncias Macromoleculares , Carbamazepina/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Bivalves/efeitos dos fármacos , Bivalves/química
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