4,500 results match your criteria Accounts Of Chemical Research[Journal]

Atomistic Polarizable Embeddings: Energy, Dynamics, Spectroscopy, and Reactivity.

Acc Chem Res 2021 May 7. Epub 2021 May 7.

Laboratoire de Chimie Théorique, Sorbonne Université, UMR 7616 CNRS, 75005 Paris, France.

ConspectusThe computational modeling of realistic extended systems, relevant in, e.g., Chemistry and Biophysics, is a fundamental problem of paramount importance in contemporary research. Read More

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SHAPE Directed Discovery of New Functions in Large RNAs.

Kevin M Weeks

Acc Chem Res 2021 May 7. Epub 2021 May 7.

Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States.

ConspectusRNA lies upstream of nearly all biology and functions as the central conduit of information exchange in all cells. RNA molecules encode information both in their primary sequences and in complex structures that form when an RNA folds back on itself. From the time of discovery of mRNA in the late 1950s until quite recently, we had only a rudimentary understanding of RNA structure across vast regions of most messenger and noncoding RNAs. Read More

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Decoding Chemical and Physical Processes Driving Plasmonic Photocatalysis Using Surface-Enhanced Raman Spectroscopies.

Acc Chem Res 2021 May 6. Epub 2021 May 6.

Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States.

ConspectusIn order to mitigate the advancing effects of environmental pollution and climate change, immediate action is needed on social, political, and industrial fronts. One segment of industry that contributes significantly to this current crisis is bulk chemical production, where fossil fuels are primarily used to drive reactions at high temperatures and pressures. Toward mitigating the environmental impact of these processes, solar energy has shown promise as a clean and renewable alternative for the photocatalytic synthesis of chemicals. Read More

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Radical Carboxylative Cyclizations and Carboxylations with CO.

Acc Chem Res 2021 May 6. Epub 2021 May 6.

Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.

ConspectusCarbon dioxide (CO) is not only a greenhouse gas and a common waste product but also an inexpensive, readily available, and renewable carbon resource. It is an important one-carbon (C1) building block in organic synthesis for the construction of valuable compounds. However, its utilization is challenging owing to its thermodynamic stability and kinetic inertness. Read More

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Biochemical Activity Architectures Visualized-Using Genetically Encoded Fluorescent Biosensors to Map the Spatial Boundaries of Signaling Compartments.

Acc Chem Res 2021 May 5. Epub 2021 May 5.

Departments of Pharmacology, Bioengineering, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.

ConspectusAll biological processes arise through the coordinated actions of biochemical pathways. How such functional diversity is achieved by a finite cast of molecular players remains a central mystery in biology. Spatial compartmentation-the idea that biochemical activities are organized around discrete spatial domains within cells-was first proposed nearly 40 years ago and has become firmly rooted in our understanding of how biochemical pathways are regulated to ensure specificity. Read More

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Analytical Cryo-Scanning Electron Microscopy of Hydrated Polymers and Microgels.

Acc Chem Res 2021 May 4. Epub 2021 May 4.

Stevens Institute of Technology Hoboken, New Jersey 07030, United States.

ConspectusDespite the fact that scanning electron microscopes (SEM) coupled with energy-dispersive X-ray microanalysis (EDS) has been commercially available for more than a half-century, SEM/EDS continues to develop and open new opportunities to study the morphology of advanced materials. This is particularly true in applications to hydrated soft matter. Developments in field-emission electron sources that enable low-voltage imaging of uncoated polymers, silicon-drift detectors that enable high-efficiency collection of X-rays characteristic of light elements, and cryogenic methods to effectively cryo-fix hydrated samples have opened new opportunities to apply techniques relatively well established in hard-materials applications to challenging new problems involving synthetic polymers. Read More

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The Chemistry of Nonclassical Taxane Diterpene.

Acc Chem Res 2021 May 4. Epub 2021 May 4.

Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany.

ConspectusThe taxane diterpenes are a pharmaceutically vital family of natural products, consisting of more than 550 congeners. All taxane diterpenes are isolated from slow growing evergreen shrubs (genus Taxus) commonly known as "yews" and have a history of over 50 years as potent anticancer compounds. The most prominent congener, taxol (paclitaxel = PTX), has been used in clinics for more than 25 years and is one of the top-selling anticancer drugs worldwide, with annual sales reaching 1. Read More

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Linear Free Energy Relationships for Enzymatic Reactions: Fresh Insight from a Venerable Probe.

Acc Chem Res 2021 May 3. Epub 2021 May 3.

Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000, United States.

ConspectusLinear free energy relationships (LFERs) for substituent effects on reactions that proceed through similar transition states provide insight into transition state structures. A classical approach to the analysis of LFERs showed that differences in the slopes of Brønsted correlations for addition of substituted alkyl alcohols to ring-substituted 1-phenylethyl carbocations and to the β-galactopyranosyl carbocation intermediate of reactions catalyzed by β-galactosidase provide evidence that the enzyme catalyst modifies the curvature of the energy surface at the saddle point for the transition state for nucleophile addition. We have worked to generalize the use of LFERs in the determination of enzyme mechanisms. Read More

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Glycosyl Oxocarbenium Ions: Structure, Conformation, Reactivity, and Interactions.

Acc Chem Res 2021 Apr 30. Epub 2021 Apr 30.

CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Spain.

ConspectusCarbohydrates (glycans, saccharides, and sugars) are essential molecules in all domains of life. Research on glycoscience spans from chemistry to biomedicine, including material science and biotechnology. Access to pure and well-defined complex glycans using synthetic methods depends on the success of the employed glycosylation reaction. Read More

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Secondary Structure in Nonpeptidic Supramolecular Block Copolymers.

Acc Chem Res 2021 Apr 29. Epub 2021 Apr 29.

Molecular Design Institute and Department of Chemistry, New York University, New York, New York 10003, United States.

ConspectusProteins contain a level of complexity-secondary and tertiary structures-that polymer chemists aim to imitate. The bottom-up synthesis of protein-mimicking polymers mastering sequence variability and dispersity remains challenging. Incorporating polymers with predefined secondary structures, such as helices and π-π stacking sheets, into block copolymers circumvents the issue of designing and predicting one facet of their 3D architecture. Read More

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Interplay of Alkali, Transition Metals, Nitrogen, and Hydrogen in Ammonia Synthesis and Decomposition Reactions.

Acc Chem Res 2021 Apr 29. Epub 2021 Apr 29.

Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.

ConspectusThe fixation of dinitrogen to ammonia is critically important for the biogeochemical cycle on earth. Ammonia also holds promise as a sustainable energy carrier. Tremendous effort has been devoted to the development of green processes and advanced materials for ammonia synthesis and decomposition under milder conditions, and encouraging progress has been made. Read More

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Plasmon-Driven Chemistry on Mono- and Bimetallic Nanostructures.

Acc Chem Res 2021 Apr 28. Epub 2021 Apr 28.

Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States.

ConspectusHot carriers are highly energetic species that can perform a large spectrum of chemical reactions. They are generated on the surfaces of nanostructures via direct interband, phonon-assisted intraband, and geometry-assisted decay of localized surface plasmon resonances (LSPRs), which are coherent oscillations of conductive electrons. LSPRs can be induced on the surface of noble metal (Ag or Au) nanostructures by illuminating the surfaces with electromagnetic irradiation. Read More

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Defining the Landscape of the Pauling-Corey Rippled Sheet: An Orphaned Motif Finding New Homes.

Acc Chem Res 2021 Apr 26. Epub 2021 Apr 26.

Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States.

ConspectusWhen peptides are mixed with their mirror images in an equimolar ratio, two-dimensional periodic structural folds can form, in which extended peptide strands are arrayed with alternating chirality. The resultant topography class, termed the rippled β-sheet, was introduced as a theoretical concept by Pauling and Corey in 1953. Unlike other fundamental protein structural motifs identified around that time, including the α-helix and the pleated β-sheet, it took several decades before conclusive experimental data supporting the proposed rippled β-sheet motif were gained. Read More

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Gas-Phase Structural Analysis of Supramolecular Assemblies.

Acc Chem Res 2021 Apr 26. Epub 2021 Apr 26.

Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20-22, 14195 Berlin, Germany.

ConspectusIon mobility spectrometry and gas-phase IR action spectroscopy are two structure-sensitive mass-spectrometric methods becoming more popular recently. While ion mobility spectrometry provides collision cross sections as a size and shape dependent parameter of an ion of interest, gas-phase spectroscopy identifies functional groups and is capable of distinguishing different isomers. Both methods have recently found application for the investigation of supramolecular assemblies. Read More

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Bioinspired Applications of Porphyrin Derivatives.

Acc Chem Res 2021 May 23;54(9):2249-2260. Epub 2021 Apr 23.

Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.

ConspectusPorphyrin derivatives are ubiquitous in nature and have important biological roles, such as in light harvesting, oxygen transport, and catalysis. Owing to their intrinsic π-conjugated structure, porphyrin derivatives exhibit characteristic photophysical and electrochemical properties. In biological systems, porphyrin derivatives are associated with various protein molecules through noncovalent interactions. Read More

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Ultrahigh-Throughput Experimentation for Information-Rich Chemical Synthesis.

Acc Chem Res 2021 Apr 23. Epub 2021 Apr 23.

Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.

ConspectusThe incorporation of data science is revolutionizing organic chemistry. It is becoming increasingly possible to predict reaction outcomes with accuracy, computationally plan new retrosynthetic routes to complex molecules, and design molecules with sophisticated functions. Critical to these developments has been statistical analysis of reaction data, for instance with machine learning, yet there is very little reaction data available upon which to build models. Read More

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Spectrally Silent Protein Reaction Dynamics Revealed by Time-Resolved Thermodynamics and Diffusion Techniques.

Acc Chem Res 2021 May 22;54(9):2238-2248. Epub 2021 Apr 22.

Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan.

ConspectusBiological functions essentially consist of a series of chemical reactions, including intermolecular interactions, and also involve the cooperation of a number of biological molecules performing these reactions. To understand this function at the molecular level, all steps of the reactions must be elucidated. However, since the biosystems including the surrounding environment are notably large, the reactions have to be elucidated from several different approaches. Read More

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Small-Molecule Tunnels in Metalloenzymes Viewed as Extensions of the Active Site.

Acc Chem Res 2021 May 22;54(9):2185-2195. Epub 2021 Apr 22.

Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55391, United States.

ConspectusRigorous substrate selectivity is a hallmark of enzyme catalysis. This selectivity is generally ascribed to a thermodynamically favorable process of substrate binding to the enzyme active site based upon complementary physiochemical characteristics, which allows both acquisition and orientation. However, this chemical selectivity is more difficult to rationalize for diminutive molecules that possess too narrow a range of physical characteristics to allow either precise positioning or discrimination between a substrate and an inhibitor. Read More

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Strategies to Combat Multi-Drug Resistance in Tuberculosis.

Acc Chem Res 2021 Apr 22. Epub 2021 Apr 22.

Drug Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa.

Conspectus""Antimicrobial resistance (AMR), is one of the most paramount health perils that has emerged in the 21st century. The global increase in drug-resistant strains of various bacterial pathogens prompted the World Health Organization (WHO) to develop a priority list of AMR pathogens. (), an acid-fast bacillus that causes tuberculosis (TB), merits being one of the highest priority pathogens on this list since drug-resistant TB (DR-TB) accounts for ∼29% of deaths attributable to AMR. Read More

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Peptides and Antibiotic Therapy: Advances in Design and Delivery.

Acc Chem Res 2021 Apr 21. Epub 2021 Apr 21.

Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics and Center for Cystic Fibrosis and Airway Diseases Research, Children's Healthcare of Atlanta, Emory University School of Medicine, 1510 Clifton Road NE, Suite 3009, Atlanta, Georgia 30322, United States.

ConspectusAntibiotic resistance (AMR) is an increasing public health crisis worldwide. This threatens our ability to adequately care for patients with infections due to multi-drug-resistant (MDR) pathogens. As such, there is an urgent need to develop new classes of antimicrobials that are not based on currently utilized antibiotic scaffolds. Read More

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Stimuli-Induced Reversible Proton Transfer for Stimuli-Responsive Materials and Devices.

Acc Chem Res 2021 May 21;54(9):2216-2226. Epub 2021 Apr 21.

State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

ConspectusStimuli-responsive materials have a great potential in various novel photoelectric devices, such as self-adaptive adjustment devices, intelligent detection, molecular computers with information storage capability, camouflage and anticounterfeiting display, various energy-saving displays, and others. However, progress in related areas has been relatively slow because of the lack of high-performance smart materials and the limitations of available reaction mechanisms currently. To address these problems fundamentally, new mechanisms need to be designed and developed, and learning from nature is an effective and intelligent method to achieve this long-awaited target, such as mimicking of proton transfer processes in nature at the molecular/supramolecular level. Read More

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Copper-Catalyzed Carbonylative Coupling of Alkyl Halides.

Acc Chem Res 2021 May 21;54(9):2261-2274. Epub 2021 Apr 21.

Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, United States.

ConspectusTransition metal-catalyzed carbonylation reactions represent a direct and atom-economical approach to introduce oxygen functionality into organic compounds, with CO acting as an inexpensive and readily available C1 feedstock. Despite the long history of carbonylation catalysis, including many processes that have been industrialized at bulk scale, there remain several challenges to tackle. For example, noble metals such as Pd, Rh, and Ir are typically used as catalysts for carbonylation reactions, rather than earth-abundant alternatives. Read More

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Current Strategies for Modulating Aβ Aggregation with Multifunctional Agents.

Acc Chem Res 2021 May 21;54(9):2172-2184. Epub 2021 Apr 21.

Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China.

ConspectusAlzheimer's disease (AD), as the primary cause of dementia, has seriously affected millions of people worldwide and brought a very heavy financial and social burden. With the growth of population and aging, the situation will worsen unless efficacious drugs are found to reverse, stop, or even slow down disease progression. More and more evidence has demonstrated that amyloid-β (Aβ) aggregation is an upstream causative factor in AD pathogenesis and then triggers a slew of pathological events. Read More

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The Enzymes of the Rifamycin Antibiotic Resistome.

Acc Chem Res 2021 May 20;54(9):2065-2075. Epub 2021 Apr 20.

M.G. DeGroote Institute for Infectious Disease Research, David Braley Center for Antibiotic Discovery, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 3Z5, Canada.

ConspectusRifamycin antibiotics include the WHO essential medicines rifampin, rifabutin, and rifapentine. These are semisynthetic derivatives of the natural product rifamycins, originally isolated from the soil bacterium . These antibiotics are primarily used to treat mycobacterial infections, including tuberculosis. Read More

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Hows and Whys of Tumor-Seeking Dyes.

Acc Chem Res 2021 May 20;54(9):2121-2131. Epub 2021 Apr 20.

Department of Chemistry, Texas A&M University, Box 30012, College Station, Texas 77842, United States.

ConspectusActive targeting uses molecular fragments that bind receptors overexpressed on cell surfaces to deliver cargoes, and this selective delivery to diseased over healthy tissue is valuable in diagnostic imaging and therapy. For instance, targeted near-infrared (near-IR) dyes can mark tissue to be excised in surgery, and radiologists can use active targeting to concentrate agents for positron emission tomography (PET) in tumor tissue to monitor tumor metastases. Selective delivery to diseased tissue is also valuable in some treatments wherein therapeutic indexes (toxic/effective doses) are key determinants of efficacy. Read More

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Total Synthesis of Complex Natural Products: More Than a Race for Molecular Summits.

Acc Chem Res 2021 Apr;54(8):1815-1816

California Institute of Technology, Pasadena, California 91125, United States.

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Efficient Heterogeneous Palladium Catalysts in Oxidative Cascade Reactions.

Acc Chem Res 2021 May 19;54(9):2275-2286. Epub 2021 Apr 19.

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.

ConspectusPalladium-catalyzed oxidations involving cascade processes provide a versatile platform for streamlined conversion of simple feedstocks into functional molecules with high atom and step economy. However, the achievement of high palladium efficiency and selectivity in Pd-catalyzed oxidative cascade reactions is still challenging in many cases, as a result of the aggregation of active palladium species to Pd black and the possible side reactions during each bond-forming step. The two current solutions for addressing these issues are either to utilize oxidant-stable ligands or to use electron transfer mediators (ETMs). Read More

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Extending Cryo-EM to Nonaqueous Liquid Systems.

Acc Chem Res 2021 May 19;54(9):2100-2109. Epub 2021 Apr 19.

Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute (RBNI), Technion-Israel Institute of Technology, Haifa 3200003, Israel.

ConspectusCryogenic-temperature transmission electron microscopy (cryo-TEM) of aqueous systems has become a widely used methodology, especially in the study of biological systems and synthetic aqueous systems, such as amphiphile and polymer solutions. Cryogenic-temperature scanning electron microscopy (cryo-SEM), while not as widely used as cryo-TEM, is also found in many laboratories of basic and applied research. The application of these methodologies, referred to collectively as cryogenic-temperature electron microscopy (cryo-EM) for direct nanostructural studies of nonaqueous liquid systems is much more limited, although such systems are important in basic research and are found in a very large spectrum of commercial applications. Read More

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2'-Fluoro-arabinonucleic Acid (FANA): A Versatile Tool for Probing Biomolecular Interactions.

Acc Chem Res 2021 May 16;54(9):2287-2297. Epub 2021 Apr 16.

Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada.

ConspectusThis Account highlights the structural features that render 2'-deoxy-2'-fluoro-arabinonucleic acid (FANA) an ideal tool for mimicking DNA secondary structures and probing biomolecular interactions relevant to chemical biology.The high binding affinity of FANA to DNA and RNA has had implications in therapeutics. FANA can hybridize to complementary RNA, resulting in a predominant A-form helix stabilized by a network of 2'F-H8(purine) pseudohydrogen bonding interactions. Read More

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Surface Fingerprinting of Faceted Metal Oxides and Porous Zeolite Catalysts by Probe-Assisted Solid-State NMR Approaches.

Acc Chem Res 2021 Apr 15. Epub 2021 Apr 15.

State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China.

ConspectusAcid catalysis in heterogeneous systems such as metal oxides and porous zeolites has been widely involved in various catalytic processes for chemical and petrochemical industries. In acid-catalyzed reactions, the performance (e.g. Read More

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