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Biomolecular condensates exhibit distinct microenvironments that arise from interactions between proteins, RNA, and solutions. In aqueous solutions, these membraneless structures constantly encounter small molecules that could affect the structure and properties of the condensates. However, the effects of organic small molecules in water solutions on the microenvironments of condensates remain poorly understood. In this study, we used various organic solutes as an example to explore how small molecules could influence the physicochemical properties in the microenvironment of protein condensates. Particularly, we quantitatively studied micropolarity and microviscosity using a combination of techniques, including fluorescence lifetime imaging microscopy, fluorescence recovery after photobleaching, and passive rheology. Unexpectedly, our results revealed that the microenvironment was not correlated with the polarity of organic solutes; instead, the correlation was observed on the interaction strength between water and small molecules. We found that solutes with stronger interaction with water and weaker interaction with proteins increase the micropolarity and decrease the microviscosity of condensates. Furthermore, we demonstrated that the modulation of the micropolarity of condensates could impact the miscibility of multicomponent condensates. Finally, we showed that organic solutes could influence the micropolarity of condensates and the partitioning of products in condensates, thus affecting the rate and equilibrium of the chemical reactions. In summary, our work provides a quantitative analysis of how the microenvironment of biomolecular condensates is impacted by organic solutes. Since protein condensates coexist with various types of metabolites in the aqueous cellular milieu, results from this work offer insights into how organic metabolites could regulate the microenvironment and behaviors of biological condensates. Show less

11,571 — — NER 2008 SCAI33 1,206 — — NER 2012 ADE39 300 case reports 5,063 drugs — 6,821 drug adverse effects 279 drug dosage RE 2013 DDI43 1,025, including texts from DrugBank and 18,502 drugs — 5,028 drug-drug interactions RE 2015 CHEMDNER34 84,355 chemicals — — NER 2016 BC5CDR 1,500 articles 15,935 chemicals 12,850 diseases 4,409 MeSH chemically induced diseases NER, NEN, RE 2017 N-ary drug-gene-mutation 35 — — — 137,469 drug–gene 3,192 drug–mutation RE 2017 40 ChemProt 32,514 chemicals 30,922 genes Show less

The Keap1-Nrf2 signaling pathway plays a crucial role in cellular defense against oxidative stress-induced damage. Its activation entails the expression and transcriptional regulation of several proteins involved in detoxification and antioxidation processes within the organism. Keap1, serving as a pivotal transcriptional regulator within this pathway, exerts control over the activity of Nrf2. Various post-translational modifications (PTMs) of Keap1, such as alkylation, glycosylation, glutathiylation, S-sulfhydration, and other modifications, impact the binding affinity between Keap1 and Nrf2. Consequently, this leads to the accumulation of Nrf2 and its translocation to the nucleus, and subsequent activation of downstream antioxidant genes. Given the association between the Keap1-Nrf2 signaling pathway and various diseases such as cancer, neurodegenerative disorders, and diabetes, comprehending the post-translational modification of Keap1 not only deepens our understanding of Nrf2 signaling regulation but also contributes to the identification of novel drug targets and biomarkers. Consequently, this knowledge holds immense importance in the prevention and treatment of diseases induced by oxidative stress. Show less

PubTator 3.0 (https://www.ncbi.nlm.nih.gov/research/pubtator3/) is a biomedical literature resource using state-of-the-art AI techniques to offer semantic and relation searches for key concepts like proteins, genetic variants, diseases and chemicals. It currently provides over one billion entity and relation annotations across approximately 36 million PubMed abstracts and 6 million full-text articles from the PMC open access subset, updated weekly. PubTator 3.0's online interface and API utilize these precomputed entity relations and synonyms to provide advanced search capabilities and enable large-scale analyses, streamlining many complex information needs. We showcase the retrieval quality of PubTator 3.0 using a series of entity pair queries, demonstrating that PubTator 3.0 retrieves a greater number of articles than either PubMed or Google Scholar, with higher precision in the top 20 results. We further show that integrating ChatGPT (GPT-4) with PubTator APIs dramatically improves the factuality and verifiability of its responses. In summary, PubTator 3.0 offers a comprehensive set of features and tools that allow researchers to navigate the ever-expanding wealth of biomedical literature, expediting research and unlocking valuable insights for scientific discovery. Show less

PubTator 3.0 (https://www.ncbi.nlm.nih.gov/research/pubtator3/) is a biomedical literature resource using state-of-the-art AI techniques to offer semantic and relation searches for key concepts like proteins, genetic variants, diseases and chemicals. It currently provides over one billion entity and relation annotations across approximately 36 million PubMed abstracts and 6 million full-text articles from the PMC open access subset, updated weekly. PubTator 3.0’s online interface and API utilize these precomputed entity relations and synonyms to provide advanced Show less

Abstract To assess the nature of the relationship between the integral conformational stability of tetrapeptides and the main types of β-turns (which are also tetrapeptides), spectrum diagrams, the asymmetry of the distribution of conformationally stable and unstable tetrapeptides have been calculated. It has been shown that β-turns of types I', II, and II' consist mainly of conformationally labile peptides; this is consistent with the context-predetermined nature of their structure. Since, as we have shown earlier, in this case the conformation is imposed by external conditions (specifically, the closure of the cycle), the prevalence of conformation-labile peptides facilitates the formation of the structure due to external factors. The type I β-turn is an exception, since peptides with different conformational lability are distributed fairly even in it. It can be assumed that the formation of the type I β-turn is not contextually determined. Show less

The ribosome is a macromolecular complex composed of RNA and proteins that interact through an integrated and interconnected network to preserve its ancient core activities. In this review, we emphasize the pivotal role played by RNA-binding proteins as a driving force in the evolution of the current form of the ribosome, underscoring their importance in ensuring accurate protein synthesis. This category of proteins includes both ribosomal proteins and ribosome biogenesis factors. Impairment of their RNA-binding activity can also lead to ribosomopathies, which is a group of disorders characterized by defects in ribosome biogenesis that are detrimental to protein synthesis and cellular homeostasis. A comprehensive understanding of these intricate processes is essential for elucidating the mechanisms underlying the resulting diseases and advancing potential therapeutic interventions. Show less

Significance: Oxidative stress is thought to account for aberrant redox homeostasis and contribute to aging and disease. However, more often than not, administration of antioxidants is ineffective, suggesting that our current understanding of the underlying regulatory processes is incomplete. Recent Advances: Similar to reactive oxygen species and reactive nitrogen species, reactive sulfur species are now emerging as important signaling molecules, targeting regulatory cysteine redox switches in proteins, affecting gene regulation, ion transport, intermediary metabolism, and mitochondrial function. To rationalize the Show less

Cytochromes (cyts) are ubiquitous heme containing proteins that are key components of energy transduction pathways. They participate in a wide variety of electron transfer reactions, which are essential for cellular processes responsible for chemical energy (ATP)... Show less

Non-covalent interactions play an important role in chemistry, physics and especially in biodisciplines. They determine the structure of biomacromolecules such as DNA and proteins and are responsible for the molecular recognition process. Theoretical evaluation of interaction energies is difficult; however, perturbation as well as variation (supermolecular) methods are briefly described. Accurate interaction energies can be obtained by complete basis set limit calculations providing a large portion of correlation energy is covered (e.g. by performing CCSD(T) calculations). The role of H-bonding and stacking interactions in the stabilisation of DNA, oligopeptides and proteins is described, and the importance of London dispersion energy is shown. Show less