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Structured RNAs are increasingly explored as novel pharmacological targets for a range of diseases. Therefore, evaluating methods for RNA-focused hit discovery is crucial. Biolayer Interferometry (BLI), a label-free technique that detects biomolecular interactions by measuring changes in white light interference near the sensor surface, offers high throughput and multiplexing capabilities. While BLI has been widely adopted for protein-targeted screening, its application in RNA-targeted drug discovery remains largely unexplored. In this study, we demonstrate the effective use of BLI to investigate RNA–small molecule interactions using three different riboswitches, which are potential targets for novel antibiotics. Furthermore, we describe the successful use of BLI to identify fragment binders of these RNA targets. We combined the BLI experiments with ligand-based NMR as an orthogonal validation method and were able to identify seven competitive fragment binders of the flavin mononucleotide (FMN) riboswitch, each featuring scaffolds distinct from the previously known ligands. Show less

Iron-sulfur (Fe-S) clusters are critical cofactors in metalloproteins, essential for cellular processes such as energy production, DNA repair, enzymatic catalysis, and metabolic regulation. While Fe-S cluster functions are intimately linked to their redox properties, their precise roles in many proteins remain unclear. In this study, we present a regression model based on experimental redox potential (E m ) data, utilizing only two features: the Fe-S cluster's total charge and the Fe atoms' average valence. This model achieves a high correlation with experimental data (R 2 = 0.82) and an average prediction error of 0.12 V. Applying this model across the Protein Data Bank, we predict E m values for all cataloged Fe-S clusters, uncovering redox potential trends across diverse cluster classes. The computed redox potentials showed strong agreement with experimental values, achieving an overall accuracy of 88%. This streamlined, computationally accessible approach enhances the annotation and mechanistic understanding of Fe-S proteins, offering new insights into the redox variability of electron transport proteins. Our model holds promise for advancing studies of metalloprotein function and facilitating the design of bioinspired redox systems. Show less

The emergence of new Mycobacterium tuberculosis (Mtb) strains resistant to the key drugs currently used in the clinic for tuberculosis treatment can substantially reduce the probability of therapy success, causing the relevance and importance of studies on the development of novel potent antibacterial agents targeting different vulnerable spots of Mtb. In this study, 28,860 compounds from the library of bioactive molecules were screened to identify novel potential inhibitors of β-ketoacyl-acyl carrier protein synthase I (KasA), one of the key enzymes involved in the biosynthesis of mycolic acids of the Mtb cell wall. In doing so, we used a structure-based virtual screening approach to drug repurposing that included high-throughput docking of the C171Q KasA enzyme with compounds from the library of bioactive molecules including the FDA-approved drugs and investigational drug candidates, assessment of the binding affinity for the docked ligand/C171Q KasA complexes, and molecular dynamics simulations followed by binding free energy calculations. As a result, post-modeling analysis revealed 6 top-ranking compounds exhibiting a strong attachment to the malonyl binding site of the enzyme, as evidenced by the values of binding free energy which are significantly lower than those predicted for the KasA inhibitor TLM5 used in the calculations as a positive control. In light of the data obtained, the identified compounds are suggested to form a good basis for the development of new antitubercular molecules of clinical significance with activity against the KasA enzyme of Mtb.Communicated by Ramaswamy H. Sarma. Show less

Life is an exergonic chemical reaction. Many individual reactions in metabolism entail slightly endergonic steps that are coupled to free energy release, typically as ATP hydrolysis, in order to go forward. ATP is almost always supplied by the rotor-stator ATP synthase, which harnesses chemiosmotic ion gradients. Because the ATP synthase is a protein, it arose after the ribosome did. What was the energy currency of metabolism before the origin of the ATP synthase and how (and why) did ATP come to be the universal energy currency? About 27 % of a cell's energy budget is consumed as GTP during translation. The universality of GTP-dependence in ribosome function indicates that GTP was the ancestral energy currency of protein synthesis. The use of GTP in translation and ATP in small molecule synthesis are conserved across all lineages, representing energetic compartments that arose in the last universal common ancestor, LUCA. And what came before GTP? Recent findings indicate that the energy supporting the origin of LUCA's metabolism stemmed from H2-dependent CO2 reduction along routes that strongly resemble the reactions and transition metal catalysts of the acetyl-CoA pathway. Show less

Ferredoxins (FDXs) are evolutionarily conserved iron-sulfur (Fe-S) proteins that serve as master regulators of mitochondrial redox homeostasis, governing critical processes including electron transfer, energy metabolism, Fe-S cluster biogenesis, and steroidogenesis. In humans, the mitochondrial isoforms FDX1 and FDX2 exhibit specialized yet complementary functions: FDX1 directs steroidogenesis, protein lipoylation, and copper redox cycling, while FDX2 is a core factor in Fe-S cluster assembly. Crucially, dysregulation of these proteins disrupts mitochondrial integrity, impairs redox balance, and activates multiple programmed cell death (PCD) pathways such as cuproptosis, ferroptosis, apoptosis, and autophagic cell death. This review systematically analyzes their isoform-specific roles in mitochondrial electron transport, Fe-S cluster dynamics, metabolic regulation, and summarizes major advances in understanding how FDX1 and FDX2 orchestrate mitochondrial-PCD crosstalk. The work further examines their critical functions in PCD execution, including FDX1-mediated cuproptosis through Cu+-dependent aggregation of lipoylated proteins and FDX2-deficiency-driven ferroptosis via Fe-S cluster collapse and iron overload. Disease mechanisms across multiple pathologies, including cancer, neurodegeneration, cardiovascular disease, endocrine disorders, and genetic syndromes, are explored, highlighting links to FDX dysfunction, with emerging therapeutic strategies targeting FDXs also addressed. By elucidating the synergistic roles of FDX1 and FDX2 as metabolic-death gatekeepers, this review establishes a foundation for developing isoform-targeted therapies against diverse pathologies. Show less

Electron transfer coupled to redox chemistry is at the heart of metabolism. The proteins responsible for moving electrons (protein electron carriers) must have emerged at the origin of life. The small iron-sulfur-binding bacterial ferredoxins were likely among these first proteins. Embedded within the ferredoxin sequence and structure is a symmetry that points to an ancient gene duplication event. Little is understood about the nature of ferredoxins prior to this duplication event or what environmental factors may have driven the selection for more complex forms. The deep-time molecular history of ferredoxins goes back billions of years and cannot be reconstructed by phylogenetic analyses based on amino acid sequences. Here, we use structure-guided protein design to model a fossil half-ferredoxin stage in the evolution of this fold, the semidoxins, and their symmetric full-length counterparts, the symdoxins. Semidoxin designs homodimerize, exhibiting structural, thermodynamic, and electrochemical behaviors in most cases identical to cognate symdoxins. However, the semi- and symdoxin fossil stages behave differently when incorporated into an in vivo electron transfer complementation assay. Both can support bacterial growth dependent on protein expression. Growth rates of bacteria expressing the semidoxins are much more sensitive to oxygen than those of bacteria expressing symdoxins. Motivated by the in vivo functionality of designed semidoxins, we identified putative naturally occurring semidoxins in extant anaerobic microorganisms. This is consistent with the observed in vivo oxygen sensitivity of the semidoxin designs. One natural semidoxin is shown to be folded and redox active. However, it exists as a mixture of monomers and dimers, suggesting a potential connection between semidoxins and even simpler single iron-sulfur cluster-binding peptides. Show less

Traditional protein engineering methods are often slow and labor-intensive. Here, authors develop an automatic protein evolution platform enabled by a protein language model. Using this platform, they significantly improved the activity of a tRNA synthetase within ten days. Show less

Protein arginine methyltransferase 1 (PRMT1) is the main PRMT family member involved in the formation of monomethylarginine and asymmetric dimethylarginine on its protein substrates. Many protein substrates of PRMT1 are key mediators of cell proliferation and oncogenesis. As such, the function of PRMT1 has been most prominently investigated in the context of cancer development. However, recent in vitro and in vivo studies have highlighted that PRMT1 may also promote metabolic disorders. With the current review, we aim to present an in-depth overview of how PRMT1 influences epigenetic modulation, transcriptional regulation, DNA damage repair, and signal transduction in cancer. Furthermore, we summarize the current knowledge regarding the role of PRMT1 in metabolic reprogramming, lipid metabolism, and glucose metabolism and describe the association of PRMT1 with numerous metabolic pathologies such as obesity, liver disease, and type 2 diabetes. It has become apparent that inhibiting the function of PRMT1 will likely serve as the most beneficial therapeutic approach, since several PRMT1 inhibitors have already been shown to exert positive effects on both cancer and metabolic disease in preclinical settings. However, pharmacological PRMT1 inhibition has not yet been shown to be therapeutically effective in clinical studies. Show less

Mutational effect transfer learning (METL) is a protein language model framework that unites machine learning and biophysical modeling. Transformer-based neural networks are pretrained on biophysical simulation data to capture fundamental relationships between protein sequence, structure and energetics. Show less

Geological structures known as alkaline hydrothermal vents (AHVs) likely displayed dynamic energy characteristics analogous to cellular chemiosmosis and contained iron-oxyhydroxide green rusts in the early Earth. Under specific conditions, those minerals could have acted as non-enzymatic catalysts in the development of early bioenergetic chemiosmotic energy systems while being integrated into the membrane of AHV-produced organic vesicles. Here, we show that the simultaneous addition of two probable AHV components, namely nickel and amino acids, impacts green rust's physico-chemical properties, especially those required for its incorporation in lipid vesicle's membranes, such as decreasing the mineral size to the nanometer scale and increasing its hydrophobicity. These results suggest that such hydrophobic nano green rusts could fit into lipid vesicle membranes and could have functioned as a primitive, inorganic precursor to modern chemiosmotic metalloenzymes, facilitating both electron and proton transport in early life-like systems. Show less

Carnitine O-acetyltransferase (CRAT) is a key mitochondrial enzyme involved in maintaining metabolic homeostasis by mediating the reversible transfer of acetyl groups between acetyl-CoA and carnitine. This enzymatic activity ensures the optimal functioning of mitochondrial carbon flux by preventing acetyl-CoA accumulation, buffering metabolic flexibility, and regulating the balance between fatty acid and glucose oxidation. CRAT’s interplay with the mitochondrial carnitine shuttle, involving carnitine palmitoyltransferases (CPT1 and CPT2) and the carnitine carrier (SLC25A20), underscores its critical role in energy metabolism. Emerging evidence highlights the structural and functional diversity of CRAT and structurally related acetyltransferases across cellular compartments, illustrating their coordinated role in lipid metabolism, amino acid catabolism, and mitochondrial bioenergetics. Moreover, the structural insights into CRAT have paved the way for understanding its regulation and identifying potential modulators with therapeutic applications for diseases such as diabetes, mitochondrial disorders, and cancer. This review examines CRAT’s structural and functional aspects, its relationships with carnitine shuttle members and other carnitine acyltransferases, and its broader role in metabolic health and disease. The potential for targeting CRAT and its associated pathways offers promising avenues for therapeutic interventions aimed at restoring metabolic equilibrium and addressing metabolic dysfunction in disease states. Show less

The double-stranded RNA editing enzyme ADAR1 connects two forms of genetic programming, one based on codons and the other on flipons. ADAR1 recodes codons in pre-mRNA by deaminating adenosine to form inosine, which is translated as guanosine. ADAR1 also plays essential roles in the immune defense against viruses and cancers by recognizing left-handed Z-DNA and Z-RNA (collectively called ZNA). Here, we review various aspects of ADAR1 biology, starting with codons and progressing to flipons. ADAR1 has two major isoforms, with the p110 protein lacking the p150 Zα domain that binds ZNAs with high affinity. The p150 isoform is induced by interferon and targets ALU inverted repeats, a class of endogenous retroelement that promotes their transcription and retrotransposition by incorporating Z-flipons that encode ZNAs and G-flipons that form G-quadruplexes (GQ). Both p150 and p110 include the Zβ domain that is related to Zα but does not bind ZNAs. Here we report strong evidence that Zβ binds the GQ that are formed co-transcriptionally by ALU repeats and within R-loops. By binding GQ, ADAR1 suppresses ALU-mediated alternative splicing, generates most of the reported nonsynonymous edits and promotes R-loop resolution. The recognition of the various alternative nucleic acid conformations by ADAR1 connects genetic programming by flipons with the encoding of information by codons. The findings suggest that incorporating G-flipons into editmers might improve the therapeutic editing efficacy of ADAR1. Show less

The transition from unregulated, prebiotic chemistry to metabolic-like systems capable of supporting an evolving protocell has remained difficult to explain. One hypothesis is that early catalysts began to prune the chemical landscape in a manner that facilitated the emergence of modern-day enzymes. As enzymes frequently rely on the intrinsic reactivity of metal ions, it follows that these early catalysts may have been metal ions coordinated to prebiotic peptides that have remained as core structures within extant proteins. Here, we demonstrate that UV light directly selects for the types of metal-binding peptide motifs found in biology. This is because bare cysteine is much more susceptible to photolysis than cysteine bound by a metal ion. Therefore, peptides with greater affinity for environmentally available metal ions, such as Fe2+ or Zn2+, are more stable. Our results are supported by mass spectrometry, calorimetry, X-ray absorption, NMR spectroscopy, transient absorption pump probe spectroscopy, and excited-state quantum-chemical calculations. Photostability arises from the ability of the metal ion to engage transiently generated reactive radical centers in a manner that prevents subsequent degradative processes. The data are consistent with the enrichment of a restricted set of high affinity, extant-like metallopeptides in surficial environments on the early Earth. Show less

Ran-binding domain-containing protein 2 (ZRANB2) is a zinc finger (ZF) protein that plays a key role in alternative splicing. ZRANB2 is composed of two ZF domains that contain four invariant cysteine residues per domain. ZRANB2 binds RNA targets that contain AGGUAA sequence motifs. Three constructs of ZRANB2, ZRANB2-ZF1 (first ZF domain), ZRANB2-ZF2 (second ZF domain), and ZRANB2-2D (both ZF domains), were isolated in the apo form and shown to bind Zn(II) via UV-visible-monitored competitive titrations with Co(II) as a spectroscopic probe. Zn binding to each construct led to the adoption of a limited secondary structure of each domain, as measured by circular dichroism (CD). Hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) of the two-domain construct, ZRANB2-2D, revealed that both ZF domains adopt a more rigid structure upon Zn binding. Zn binding to the first ZF domain resulted in a greater decrease in the conformational dynamics than Zn binding to the second ZF domain. RNA binding to TRA2B pre-mRNA, a physiological splicing target, was measured by fluorescence anisotropy (FA), and high-affinity RNA binding was found to require Zn coordination to both domains. HDX-MS of ZRANB2-2D with TRA2B RNA as well as two optimized RNA sequences that contain a single and double AGGUAA hexamer revealed additional protection from H/D exchange for ZRANB2 in the presence of RNA. Here, greater protection was observed for the second ZF of ZRANB2-2D, suggesting a larger effect on conformational dynamics. A model for zinc-mediated RNA binding of ZRANB2 is proposed. Show less

The development of a universal protein coarse-grained model has been a long-standing challenge. A coarse-grained model with chemical transferability has now been developed by combining deep-learning methods with a large and diverse training set of all-atom protein simulations. The model can be used for extrapolative molecular dynamics on new sequences. Show less

Polyamines, namely putrescine, spermidine and spermine, are involved in multiple molecular pathways through their ability to bind nucleic acids and modulate protein stability. Their intracellular level is regulated through biosynthesis, catabolism and uptake from the extracellular milieu and the disruption of their homeostasis contributes to a variety of human disorders including cancer, as mainly described in solid tumors. Recently, there is an increasing interest in understanding polyamine functions in acute leukemias, due to the linkage between leukemic gene drivers, polyamine metabolism alterations and epigenetic defects. In particular, polyamine involvement in the regulation of acetylation and methylation is clinically relevant since epigenetic drugs are currently the backbone of novel therapeutic combinations, especially in acute myeloid leukemia (AML). With the exception of methylthioadenosine phosphorylase (MTAP), the enzyme leading to methionine regeneration that is frequently deleted in acute lymphoblastic leukemia (ALL), genes involved in polyamine metabolism and the interconnected methionine and arginine pathways are rarely targets of genetic lesions in acute leukemias. Conversely, functional alterations, including elevated polyamine levels and deregulated activity of enzymes involved in their metabolism, have been recently reported in leukemic cells. Notably, the polyamine catabolic enzyme spermidine/spermine N1 acetyltransferase (SAT1) that is overexpressed in AML and associated with a myeloproliferative phenotype, is a tumor suppressor gene in ALL, suggesting diverse mechanisms of action across hematological malignancies according to the lineage commitment and the differentiation stage. In light of the promising results achieved in AML and ALL by selective targeting of protein arginine methyltransferase 5 (PRMT5) and methionine adenosyltransferase 2A (MAT2A), two enzymes at the crossroad between polyamine metabolism and protein methylation, in this review we examine and discuss the role of polyamines in epigenetic regulation and other biological processes supporting leukemic cell survival, proliferation and differentiation, which provides the opportunity to discover additional polyamine-related targets and design novel therapeutic combinations. Show less

This study presents a protein search framework with conformal prediction, enabling statistically reliable annotation of protein function. The method improves homology search, enzyme classification, and filters proteins for further characterization. Show less

Studies by microbiologists in the 1970s provided robust estimates for the energy supply and demand of a prokaryotic cell. The amount of ATP needed to support growth was calculated from the chemical composition of the cell and known enzymatic pathways that synthesize its constituents from known substrates in culture. Starting in 2015, geneticists and evolutionary biologists began investigating the bioenergetic role of mitochondria at eukaryote origin and energy in metazoan evolution using their own, widely trusted-but hitherto unvetted-model for the costs of growth in terms of ATP per cell. The more recent model contains, however, a severe and previously unrecognized error that systematically overestimates the ATP cost of amino acid synthesis up to 200-fold. The error applies to all organisms studied by such models and leads to conspicuously false inferences, for example that the synthesis of an average amino acid in humans requires 30 ATP, which no biochemistry textbook will confirm. Their ATP 'cost' calculations would require that E. coli obtains ~100 ATP per glucose and that mammals obtain ~240 ATP per glucose, untenable propositions that invalidate and void all evolutionary inferences so based. By contrast, established methods for estimating the ATP cost of microbial growth show that the first mitochondrial endosymbionts could have easily doubled the host's available ATP pool, provided (i) that genes for growth on environmental amino acids were transferred from the mitochondrial symbiont to the archaeal host, and (ii) that the host for mitochondrial origin was an autotroph using the acetyl-CoA pathway. Stated in simple terms, the significance of these findings are this: Life is a chemical reaction. It requires energy release in order to proceed. The currency of energy in cells is adenosine triphosphate, ATP. Five decades ago, microbiologists were able to measure and understand the amount of ATP that cells require to grow. New studies by evolutionary biologists have appeared in the meantime that brush aside the older microbiological findings, using their own methods to calculate the ATP cost of growth instead. Science is, however, an imperfect undertaking. The new studies contain a major error, similar to conflating centimeters with yards. The error affects many publications and their conclusions. Using the old methods, we can still meaningfully study the role of energy in evolution, including the origin of complex, nucleus-bearing cells. Show less

All known living systems make proteins from the same 20 canonically coded amino acids, but this was not always the case. Early genetic coding systems likely operated with a restricted pool of amino acid types and limited means to distinguish between them. Despite this, amino acid substitution models like LG and WAG all assume a constant coding alphabet over time. That makes them especially inappropriate for the aminoacyl-tRNA synthetases (aaRS)-the enzymes that govern translation. To address this limitation, we created a class of substitution models that account for evolutionary changes in the coding alphabet size by defining the transition from 19 states in a past epoch to 20 now. We use a Bayesian phylogenetic framework to improve phylogeny estimation and testing of this two-alphabet hypothesis. The hypothesis was strongly rejected by datasets composed exclusively of "young" eukaryotic proteins. It was generally supported by "old" (aaRS and non-aaRS) proteins whose origins date from before the last universal common ancestor. Standard methods overestimate the divergence ages of proteins that originated under reduced coding alphabets in both simulated and aaRS alignments. The new model provides a timeline slightly more consistent with the Earth's history. Our findings suggest that aaRS functional bifurcation events can explain much of the genetic code's evolution, but there remain other unknown forces at play too. This work provides a robust, seamless framework for reconstructing phylogenies from ancient protein datasets and offers further insights into the dawn of molecular biology. Show less

Proteins are of great significance in living organisms. However, understanding their functions encounters numerous challenges, such as insufficient integration of multimodal information, a large number of training parameters, limited flexibility of classification-based methods, and the lack of systematic evaluation metrics for protein question answering systems. To tackle these issues, we propose the Prot2Chat framework. Show less

Tetrazoles are nitrogen-rich heterocycles that have attracted interest because of their numerous applications in pharmaceutical and medicinal chemistry. Four nitrogen atoms and one carbon atom make up these five-membered rings, which have special physicochemical and electrical characteristics, including acidity, resonance stabilization, and aromaticity. This article highlights the structure, spectroscopic characteristics, and physical and chemical characteristics of tetrazoles. It also describes how overlapping mechanisms, such as DNA replication inhibition, protein synthesis disruption, and oxidative stress induction, as well as similar therapeutic targets, enable inhibitors to serve as both antibacterial and anticancer agents. Tetrazole moieties have been fused with a range of pharmacophores, such as indoles, pyrazoles, quinolines, and pyrimidines, yielding fused derivatives that display substantial inhibitory activity against bacterial, fungal, and cancer cell lines, with certain compounds exhibiting efficacy comparable to or exceeding that of established therapeutic agents. The rational design of more efficacious tetrazole-based therapies is facilitated by structure-activity relationship analysis, which further highlights significant functional groups and scaffolds that contribute to increasing activity. We investigate the relationship between microbial inhibition and anticancer efficacy, opening up new avenues for the creation of multifunctional therapeutic agents. We hope that this study will offer significant guidance and serve as a valued resource for medicinal and organic researchers working on drug development and discovery in multifunctional therapeutics. The review involves a thorough investigation of tetrazole in recent years. Show less

Early in the evolution of life, a proto-metabolic network was encapsulated within a membrane compartment. The permeability characteristics of the membrane determined several key functions of this network by determining which compounds could enter the compartment and which compounds could not. One key feature of known life is the utilization of right-handed d-ribose and d-deoxyribose sugars and left-handed l-amino acid stereochemical isomers (enantiomers); however, it is not clear why life adopted this specific chirality. Generally, archaea have l-phospholipid membrane chemistries and bacteria and eukaryotes have d-phospholipid membrane chemistries. We previously demonstrated that an l-archaeal and a d-intermediate membrane mimic, bearing a mixture of bacterial and archaeal lipid characteristics (a 'hybrid' membrane), displayed increased permeability for several key compounds compared to bacterial-like membranes. Here, we investigate if these membranes can drive stereochemical selection on pentose sugars, hexose sugars, and amino acids. Using permeability assays of homogenous unilamellar vesicles, we demonstrate that both membranes select for d-ribose and d-deoxyribose sugars while the hybrid membrane uniquely selects for a reduced alphabet of l-amino acids. This repertoire includes alanine, the plausible first l-amino acid utilized. We conclude such compartments could provide stereochemical compound selection matching those used by the core metabolism of life. Show less

Influenza A viruses (IAVs) are single-stranded negative-sense RNA viruses that continually challenge animal and human health. In IAV-infected cells, host RNA-binding proteins play key roles in the life cycle of IAV by directly binding to viral RNA. Here, we examined the role of the host RNA-binding protein nucleophosmin-1 (NPM1) in IAV replication. We found that, as a nucleolar phosphoprotein, NPM1 directly binds to viral RNA (vRNA) and inhibits the replication of various subtypes of IAV. NPM1 binding to vRNA competitively reduces the assembly of the viral ribonucleoprotein complex and the viral polymerase activity, thereby reducing the generation of progeny viral RNA and virions. The RNA-binding activity of NPM1, with the key residues T199, T219, T234, and T237, is essential for its anti-influenza function. Taken together, our findings demonstrate that NPM1 acts as an RNA-binding protein and interacts with IAV vRNA to suppress viral replication. Show less

N-acetyl-l-cysteine (NAC) is a medication and a widely used antioxidant in cell death research. Despite its somewhat obscure mechanism of action, its role in inhibiting ferroptosis is gaining increasing recognition. In this study, we demonstrate that NAC treatment rapidly replenishes the intracellular cysteine pool, reinforcing its function as a prodrug for cysteine. Interestingly, its enantiomer, N-acetyl-d-cysteine (d-NAC), which cannot be converted into cysteine, also exhibits a strong anti-ferroptotic effect. We further clarify that NAC, d-NAC, and cysteine all act as direct reducing substrates for GPX4, counteracting lipid peroxidation. Consequently, only GPX4-rather than system xc-, glutathione biosynthesis, or ferroptosis suppressor protein 1-is necessary for NAC and d-NAC to prevent ferroptosis. Additionally, we identify a broad range of reducing substrates for GPX4 in vitro, including β-mercaptoethanol. These findings provide new insights into the mechanisms underlying the protective effects of NAC and other potential GPX4-reducing substrates against ferroptosis. Show less

RNA and proteins are two crucial players in the origin of life but while RNA evolved to assemble proteins from amino acids, a significant mirror-symmetric effect of amino acids to trigger the synthesis of RNA was missing. Here, the authors report ambient alkaline conditions where amino acids, without additional chemical activators, promote RNA copolymerisation more than 100-fold, starting from prebiotically plausible ribonucleoside-2′,3′-cyclic phosphates. Show less

For life to emerge on Earth, peptides must first have formed without the aid of enzymes — but how? Reactions of sulfur-containing molecules might have been key. For life to emerge on Earth, peptides must first have formed without the aid of enzymes — but how? Reactions of sulfur-containing molecules might have been key. Show less

Glycolysis stops where gluconeogenesis starts-at pyruvate, the central metabolite of biosynthesis. The early history of carbon metabolism is preserved in archaeal and bacterial enzymes for glucose synthesis and breakdown. Here, we summarize the distribution and phylogeny of enzymes involved in glycolysis, gluconeogenesis, and glycogen metabolism from genomes of cultured prokaryotes. The presence of glycolytic pathways in H2-dependent chemolithoautotrophs, including methanogens, which cannot grow on exogenous glucose, correlates with their use of glycogen for intracellular carbon storage. Glycogen synthesis and gluconeogenesis are universal among prokaryotes, but glycolysis is not, indicating that the enzymatic conversions of glycolysis arose in the gluconeogenic direction encompassing three phases: (1) an autotrophic origin from H2 and CO2 to pyruvate and triosephosphate (trunk glycolysis) fulfilling basic amino acid and cofactor synthesis in the last universal common ancestor, (2) from triosephosphate to glucose supplying cell wall (murein and pseudomurein) and nucleic acid biosynthetic requirements in the first free-living autotrophs, also giving rise to intracellular carbon reserves (glycogen), followed by (3) diversification and transfer of enzymes for glycogen-mobilizing glycolytic routes. An autotrophic origin of trunk glycolysis followed by glycogen-dependent origin of glucose utilization account for conservation, distribution, and diversity of enzymes observed in microbial sugar phosphate pathways. Show less

Ferroptosis is a regulated form of cell death characterized by iron-dependent lipid peroxidation. It plays a crucial role in various pathological conditions, including neurodegenerative diseases, cancer, ischemia-reperfusion injury, and organ failure. This review systematically explores the key mechanisms underlying ferroptosis, including polyunsaturated fatty acid-containing phospholipid (PUFA-PL) peroxidation, iron metabolism, and mitochondrial dysfunction. Additionally, we summarize major endogenous ferroptosis defense systems, including the SLC7A11-glutathione (GSH)-glutathione peroxidase 4 (GPX4) axis, the ferroptosis suppressor protein 1 (FSP1)-ubiquinol (CoQH₂) system, the mitochondrial dihydroorotate dehydrogenase (DHODH)-CoQH₂ pathway, and the guanosine triphosphate cyclohydrolase 1 (GCH1)-tetrahydrobiopterin (BH4) pathway, which act as critical brakes on ferroptosis. Furthermore, we discuss various small-molecule inhibitors targeting ferroptosis, categorized by their mechanisms of action, including iron chelators, lipid peroxidation inhibitors, antioxidants, and regulatory pathway modulators. Recent advances in pharmacological strategies and their potential therapeutic applications are also highlighted. Show less

Serpentinizing hydrothermal vents are likely sites for the origin of metabolism because they produce H2 as a source of electrons for CO2 reduction while depositing zero-valent iron, cobalt, and nickel as catalysts for organic reactions. Recent work has shown that solid-state nickel can catalyze the H2-dependent reduction of CO2 to various organic acids and their reductive amination with H2 and NH3 to biological amino acids under the conditions of H2-producing hydrothermal vents and that amino acid synthesis from NH3, H2, and 2-oxoacids is facile in the presence of Ni0. Such reactions suggest a metallic origin of metabolism during early biochemical evolution because single metals replace the function of over 130 enzymatic reactions at the core of metabolism in microbes that use the acetyl-CoA pathway of CO2 fixation. Yet solid-state catalysts tether primordial amino synthesis to a mineral surface. Many studies have shown that pyridoxal catalyzes transamination reactions without enzymes. Here we show that pyridoxamine, the NH2-transferring intermediate in pyridoxal-dependent transamination reactions, is generated from pyridoxal by reaction with NH3 (as little as 5 mm) and H2 (5 bar) on Ni0 as catalyst at pH 11 and 80 °C within hours. These conditions correspond to those in hydrothermal vents undergoing active serpentinization. The results indicate that at the origin of metabolism, pyridoxamine provided a soluble, organic amino donor for aqueous amino acid synthesis, mediating an evolutionary transition from NH3-dependent amino acid synthesis on inorganic surfaces to pyridoxamine-dependent organic reactions in the aqueous phase. Show less

We hypothesize that the first ancestral "protocell" molecular structures, i.e., the first RNAs and peptides that gradually transformed into real cells once the Earth had cooled sufficiently for organic molecules to appear, have left traces in the RNAs and the genes in present cells. We propose a circular RNA that could have been one of these ancestral structures whose vestigial pentameric subsequences would mark the evolution from this key moment when the protocells began to join with living organisms. In particular, we propose that, in present RNAs (ribosomal or messenger), which play an important role in the metabolism of current cells, we look for traces of the proposed primitive structure in the form of pentamers (or longer fragments) that belong to their nucleotide sequence. The result obtained can be summarized in the existence of a gradient of occurrence of such pentamers, with a high frequency for the most vital functions (protein synthesis, nucleic synthesis, cell respiration, etc.). This gradient is also visible between organisms, from the oldest (Archaea) to the most recent (Eukaryotes) in the evolution of species. Show less