Transfer RNA (tRNA) is present at tens of millions of transcripts in a human cell and is the most abundant RNA in moles among all cellular RNAs. tRNA is also the most extensively modified RNA with, ...on an average, 13 modifications per molecule. The primary function of tRNA as the adaptor of amino acids and the genetic code in protein synthesis is well known. tRNA modifications play multi-faceted roles in decoding and other cellular processes. The abundance, modification, and aminoacylation (charging) levels of tRNAs contribute to mRNA decoding in ways that reflect the cell type and its environment; however, how these factors work together to maximize translation efficiency remains to be understood. tRNAs also interact with many proteins not involved in translation and this may coordinate translation activity and other processes in the cell. This review focuses on the modifications and the functional genomics of human tRNA and discusses future perspectives on the explorations of human tRNA biology.
The composition of the cellular proteome is commonly thought to strictly adhere to the genetic code. However, accumulating evidence indicates that cells also regulate the synthesis of mutant protein ...molecules that deviate from the genetic code. Production of mutant proteins generally occurs when cells are stressed or when they undergo environmental adaptation, but production varies in amounts and specificity. The deliberate synthesis of mutant proteins suggests that some of these proteins can be useful in cellular stress response and adaptation. This review describes the occurrence of, the translation mechanisms for, and the functional hypotheses on regulated synthesis of mutant proteins.
Abstract
In this study, we present a straightforward and environmentally friendly electrochemical approach for achieving selective halogenation of N‐heteroarenes, including indoles, diazoles, ...pyrroles, quinolinone, and naphthols. Our method utilizes commercially available and affordable ammonium halides as halogen source. A library of valuable halogenated N‐heteroarenes can be synthesized in moderate to excellent yields under mild conditions (transition‐metal‐free, oxidant‐free, ethanol as solvent, atmospheric environment). The approach demonstrates a broad substrate scope, excellent tolerance towards various functional groups, and scalability.
Digitalization has emerged as an indispensable pathway for enterprises aiming to achieve low-carbon development, demanding strategic implementation by managers who play a crucial role in shaping ...organizational outcomes. This study utilizes text mining and IPCC methods (based on The Intergovernmental Panel on Climate Change standards) to assess the level of digital transformation and enterprise carbon emission intensity among Shanghai and Shenzhen A-share listed companies from 2008 to 2015. This study also investigates the impact of digital transformation on enterprise carbon emission intensity and examines the influence of myopic characteristics among managers along with their underlying mechanisms. The results indicate that: (1) Digital transformation decreases enterprise carbon emission intensity, with robust results supported by instrumental variable test, the Oster test, confounding variable threshold impact test, etc. (2) Heterogeneity analysis demonstrates that digital transformation is particularly effective in reducing enterprise carbon emission intensity for companies located in cities without national carbon trading pilot policies, heavy industrial sectors, and those influenced by peer effects. (3) The study on mechanisms reveals that management myopia poses a barrier to the decarbonization process driven by digitalization. It further explores the moderating effects of green innovation, sustainable investment, and environmental awareness, revealing that management constrained by innovation myopia, investment myopia, and environmental responsibility myopia faces challenges in promoting decarbonization. By examining the internal aspects of management myopia, we provide valuable insights and recommendations for enterprises seeking to achieve decarbonization through digital transformation.
Proper control of the transcriptome is key for diverse aspects of gene expression, cellular functions and development, and its disruption can result in disease. A rapidly accumulating wealth of ...studies are identifying and functionally characterizing diverse types of RNA base modifications in protein-coding and non-coding RNAs, which have energized the emerging field of 'epitranscriptomics'. In this Viewpoint article, five experts discuss our latest understanding of RNA modifications, including recommendations for best practices and visions for the future.
Prussian blue analogs are well suited for sodium-ion battery cathode materials due to their cheap cost and high theoretical specific capacity. Na
CoFe(CN)
(CoHCF), one of the PBAs, has poor rate ...performance and cycling stability, while Na
FeFe(CN)
(FeHCF) has better rate and cycling performance. The CoHCF@FeHCF core-shell structure is designed with CoHCF as the core material and FeHCF as the shell material to enhance the electrochemical properties. The successfully prepared core-shell structure leads to a significant improvement in the rate performance and cycling stability of the composite compared to the unmodified CoHCF. The composite sample of core-shell structure has a specific capacity of 54.8 mAh g
at high magnification of 20 C (1 C = 170 mA g
). In terms of cycle stability, it has a capacity retention rate of 84.1% for 100 cycles at 1 C, and a capacity retention rate of 82.7% for 200 cycles at 5 C. Kinetic analysis shows that the composite sample with the core-shell structure has fast kinetic characteristics, and the surface capacitance occupation ratio and sodium-ion diffusion coefficient are higher than those of the unmodified CoHCF.
Although the synthesis of α‐tertiary amino acids (ATAAs) has been extensively studied, the development of an inexpensive and facile methodology to incorporate multifunctionality on ATAAs remains ...challenging. In this article, we present a single‐step radical approach for the modular synthesis of functionally diverse ATAAs. This synthesis takes place under mild conditions with an absence of metals, photocatalysts, and all other additives. We demonstrate the broad applications of this approach on a variety of aliphatic and aromatic carboxylic acids, alkenes, 1,3‐enynes, and oxazolones. The results prove that our method provides excellent functional group tolerance and late‐stage applicability, as well as gram‐scale synthesis via flow chemistry. Additionally, we include mechanistic studies which reveal that the excited state of oxazolone enolate upon light excitation is a key intermediate that acts as a radical precursor and an efficient reductant.
Reported herein is a highly selective radical cascade‐cross‐coupling reaction for the modular synthesis of α‐tertiary amino acids (ATAA) under mild conditions. Mechanistic studies reveal the excited state of an in situ‐generated oxazolone enolate as a key intermediate, which functions both as a radical precursor and an efficient reductant.
An emerging body of evidence indicates that post-transcriptional gene regulation relies not only on the sequence of mRNAs but also on their folding into intricate secondary structures and on the ...chemical modifications of the RNA bases. These features, which are highly dynamic and interdependent, exert direct control over the transcriptome and thereby influence many aspects of cell function. Here, we consider how the coupling of RNA modifications and structures shapes RNA-protein interactions at different steps of the gene expression process.
The oxindole scaffold represents an important structural feature in many natural products and pharmaceutically relevant molecules. Herein, we report a visible-light-induced modular methodology for ...the synthesis of complex 3,3'-disubstituted oxindole derivatives. A library of valuable fluoroalkyl-containing highly sterically congested oxindole derivatives can be synthesized by a catalytic three-component radical coupling reaction under mild conditions (metal & photocatalyst free, >80 examples). This strategy shows high functional group tolerance and broad substrate compatibility (including a wide variety of terminal or non-terminal alkenes, conjugated dienes and enynes, and a broad array of polyfluoroalkyl iodide and oxindoles), which enables modular modification of complex drug-like compounds in one chemical step. The success of solar-driven transformation, large-scale synthesis, and the late-stage functionalization of bioactive molecules, as well as promising tumor-suppressing biological activities, highlights the potential for practical applications of this strategy. Mechanistic investigations, including a series of control experiments, UV-vis spectroscopy and DFT calculations, suggest that the reaction underwent a sequential two-step radical-coupling process and the photosensitive perfluoroalkyl benzyl iodides are key intermediates in the transformation.
The oxidation of cyclohexanone with nitric acid in microreactors, as a representative chemical reaction with in situ gas production, was selected as the model reaction for computational fluid ...dynamics (CFD) modeling. The reaction kinetics was coupled with the CFD model by user‐defined functions (UDFs) to obtain the velocity field of liquid phase, the concentration field of products, and the temperature field of gas–liquid phases during the reaction process. The simulation results were then validated by the experimental data. Based on the established model, the fluid flow behavior and mass transfer characteristics during the in situ gas production process in a microreactor were further analyzed. Finally, the effects of channel diameter and bubble velocity on gas–liquid interfacial mass transfer were investigated. This work provides an effective method for studying in situ gas production processes through modeling and simulation, which is valuable in the design and optimization of tubular reactors.
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