Enzyme Function Research Articles

Concentration and activation biresponsive strategy in one analysis system with simultaneous use of G4 structure-specific signal probe and enzyme-catalyzed reaction

BackgroundEnzymes with critical effects on life systems are regulated by expression and activation to modulate life processes. However, further insights into enzyme functions and mechanisms in various physiological processes are limited to concentration or activation analysis only. Currently, enzyme analysis has received notable attention, particularly simultaneous analysis of their concentration and activation in one system. Herein, N-methyl mesoporphyrin IX (NMM), a specific dye with notable structural selectivity for parallel G-quadruplex nucleic acid enzyme (G4h DNAzyme), is employed for the analysis of its concentration. In addition, the peroxidase activity of G4h DNAzyme is characterized based on G4h DNAzyme–catalyzed decomposition of H2O2 to continuously consume luminol. Accordingly, an increased fluorescence (FL) response of NMM and a decreased FL response of luminol could be simultaneously employed to analyze the concentration and activation of G4h DNAzyme. ResultHerein, a novel concentration and activation biresponsive strategy is proposed using a G4h DNAzyme–based model that simultaneously employs a G4h structure–specific signal probe for enzyme concentration analysis and G4h DNAzyme–catalyzed reactions for enzyme activation analysis. Under optimal conditions, the biresponsive strategy can be effectively used for the simultaneous analysis of G4h DNAzyme concentration and activation, with detection limits of 718.7 pM and 233.4 nM respectively, delivering acceptable performances both in cell and in vitro. SignificanceThis strategy can not only be applied to concentration and activation analyses of G4h DNAzyme but can also be easily extended to other enzymes by simultaneously combining concentration analysis via target-induced direct reaction and activation analysis via target-induced catalytic reaction, offering deeper insights into various enzymes and enabling their effective implementation in bioanalysis and biochemistry.

Outstanding enhancement of caproate production with microwave pyrolyzed highly reductive biochar addition

The integration of biochar into microbial Chain Elongation (CE) proves to be an effective tool of producing high-value bio-based products. This study innovatively applied biochar fabricated under microwave irradiation with carbon fiber cloth assistance into CE system. Results highlighted that microwave biochar achieved maximal CE efficiency yielding 8 g COD/L, with 3-fold increase to the blank group devoid of any biochar. Microwave biochar also obtained the highest substrate utilization rate of 94 %, while conventional biochar group recorded 90 % and the blank group was of 74 %. Mechanistic insights revealed that the reductive surface properties facilitated CE performance, which is relevant to fostering dominant genera of Parabacteroides, Bacteroides, and Macellibacteroides. By metagenomics, microwave biochar up-regulated functional genes and enzymes involved in CE process including ethanol oxidation, the reverse β-oxidation pathway, and the fatty acid biosynthesis pathway. This study effectively facilitated caproate production by utilizing a new microwave biochar preparation strategy.

Identification of a Polypeptide Inhibitor of O-GlcNAc Transferase with Picomolar Affinity.

O-GlcNAc transferase (OGT) is an essential mammalian enzyme that binds thousands of different proteins, including substrates that it glycosylates and nonsubstrate interactors that regulate its biology. OGT also has one proteolytic substrate, the transcriptional coregulator host cell factor 1 (HCF-1), which it cleaves in a process initiated by glutamate side chain glycosylation at a series of central repeats. Although HCF-1 is OGT's most prominent binding partner, its affinity for the enzyme has not been quantified. Here, we report a time-resolved Förster resonance energy transfer assay to measure ligand binding to OGT and show that an HCF-1-derived polypeptide (HCF3R) binds with picomolar affinity to the enzyme (KD ≤ 85 pM). This high affinity is driven in large part by conserved asparagines in OGT's tetratricopeptide repeat domain, which form bidentate contacts to the HCF-1 peptide backbone; replacing any one of these asparagines with alanine reduces binding by more than 5 orders of magnitude. Because the HCF-1 polypeptide binds so tightly to OGT, we tested its ability to inhibit enzymatic function. We found that HCF3R potently inhibits OGT both in vitro and in cells and used this finding to develop a genetically encoded, inducible OGT inhibitor that can be degraded with a small molecule, allowing for reversible and tunable inhibition of OGT.

Transcriptional Regulation and Function of Malic Enzyme 1 in Human Macrophage Activation.

Macrophages represent primary players of the innate immune system. Macrophage activation triggers several signaling pathways and is tightly associated with metabolic changes, which drive different immune subsets. Recent studies unveil the role of various metabolic enzymes in macrophage activation. Here, we show that malic enzyme 1 (ME1) is overexpressed in LPS-induced macrophages. Through chromatin immunoprecipitation, we demonstrate that ME1 transcriptional regulation is under control of NF-κB. Furthermore, ME1 activity is also increased in activated human PBMC-derived macrophages. Notably, ME1 gene silencing decreases nitric oxide as well as reactive oxygen species and prostaglandin E2 inflammatory mediators. Therefore, modulating ME1 provides a potential approach for immunometabolic regulation and in turn macrophage function.

Microbial fuel cell-assisted composting shows stronger capacity to immobilize phosphorus: Emphasized on bacterial structures and functional enzymes

Limited scientific evidence exists on phosphorus immobilization under autogenetic electrochemical reactions in composting systems. This study exploited a composting procedure using microbial fuel cell (MFC) to ascertain phosphorus redistribution during composting process. Compared to the control without MFC equipment, MFC-assisted treatment yielded a 13 % decrease in phosphorus availability due to the transformation of exchangeable fraction (Ex-P) to aluminum-bound (Al-P) and calcium-bound (Ca-P) fractions. During the composting process, organic humification primarily controlled phosphorus redistribution and immobilization. Biotic factors, including bacterial communities (i.e., Firmicutes, Proteobacteria, Bacteroidota, and Gemmatimonadota) and functional enzymes (i.e., acid phosphatase, alkaline phosphatase, phytase, and C-P lyase), significantly influenced phosphorus availability in the composting systems. Temperature-dependent composting phases restricted microbial actions on phosphorus transformation. These findings highlight the mechanisms underlying phosphorus transformation in composting systems, and provide valuable insights for advancing composting technology and protecting agricultural ecosystems.

Identification of a Compound Inhibiting Both the Enzymatic and Nonenzymatic Functions of Indoleamine 2,3-Dioxygenase 1.

Indoleamine 2,3-dioxygenase 1 (IDO1) plays a key role in tumor immune escape. Besides being a metabolic enzyme that catalyzes the first step of tryptophan catabolism, it also acts as a signal-transducing protein, whose partnering with tyrosine phosphatase Src homology 2 (SH2) domain-containing protein tyrosine phosphatase substrate (SHPs) and phosphatidylinositol-3-kinase (PI3K) regulatory subunit p85 promotes the establishment of a sustained immunosuppressive phenotype. While IDO1 inhibitors typically interfere with its enzymatic activity, we aimed to discover a more effective modulator capable of blocking not only the enzymatic but also the signaling-mediated functions of IDO1. By virtual screening, we identified the compound VS-15, which selectively binds the heme-free form of IDO1, inhibits its enzymatic activity, and reduces the IDO1-mediated signaling pathway by negatively interfering with its partnership with SHPs and PI3K regulatory subunit p85 as well as with the IDO1 anchoring to the early endosomes in tumor cells. Moreover, VS-15 counteracts the TGF-β-mediated immunosuppressive phenotype in dendritic cells and reduces the level of inhibition of T cell proliferation by suppressive monocytes isolated from patients affected by pancreatic cancer. Herein, we describe the discovery and characterization of a small molecule with an unprecedented mechanism of action, capable of inhibiting both the enzymatic and nonenzymatic activities of IDO1 by binding to its apo-form. These results pave the way for the development of next-generation IDO1 inhibitors with a unique competitive advantage over the currently available modulators, thereby opening therapeutic opportunities in cancer immunotherapy.

Explainable Machine Learning Model to Accurately Predict Protein-Binding Peptides

Enzymes play key roles in the biological functions of living organisms, which serve as catalysts to and regulate biochemical reaction pathways. Recent studies suggest that peptides are promising molecules for modulating enzyme function due to their advantages in large chemical diversity and well-established methods for library synthesis. Experimental approaches to identify protein-binding peptides are time-consuming and costly. Hence, there is a demand to develop a fast and accurate computational approach to tackle this problem. Another challenge in developing a computational approach is the lack of a large and reliable dataset. In this study, we develop a new machine learning approach called PepBind-SVM to predict protein-binding peptides. To build this model, we extract different sequential and physicochemical features from peptides and use a Support Vector Machine (SVM) as the classification technique. We train this model on the dataset that we also introduce in this study. PepBind-SVM achieves 92.1% prediction accuracy, outperforming other classifiers at predicting protein-binding peptides.

Organic Trace Minerals Enhance the Gut Health of British Shorthair Cats by Regulating the Structure of Intestinal Microbiota.

Trace minerals are essential for biological processes, including enzyme function, immune response, and hormone synthesis. The study assessed the effects of different dietary trace minerals on the gut health, microbiota composition, and immune function of cats. Eighteen adult British Shorthair cats were divided into three groups receiving inorganic trace minerals (ITM), a 50/50 mix of inorganic and organic trace minerals (ITM + OTM), or organic trace minerals (OTM) for 28 days. The OTM showed enhanced immune capacities, reduced intestinal barrier function, and lower inflammation condition. The OTM altered gut microbiota diversity, with a lower Simpson index and higher Shannon index (p < 0.05). Specifically, the abundance of Bacteroidota, Lachnospiraceae, and Prevotella in the OTM group were higher than the ITM group (p < 0.05). Metabolomic analysis identified 504 differential metabolites between the OTM and ITM groups (p < 0.05, VIP-pred-OPLS-DA > 1), affecting pathways related to steroid hormone biosynthesis and glycerophospholipid metabolism (p < 0.05, VIP-pred-OPLS-DA > 2). Additionally, there was a significant correlation between intestinal microbiota and differential metabolites. To conclude, dietary OTM can modulate the gut metabolite and microbiota composition, enhance immune and intestinal barrier function, and mitigate inflammation in cats, highlighting the benefit of using OTM in feline diet to promote the intestinal and overall health.

Insights into the individual and combined effects of Cu(Ⅱ) and Ni(Ⅱ) on anammox: Nitrogen removal performance, enzyme activity and microbial community

Anaerobic ammonium oxidation (anammox) is an efficient and economical nitrogen removal process for treating ammonium-rich industrial wastewaters. However, Cu(Ⅱ) and Ni(Ⅱ) present in industrial wastewaters are toxic to anaerobic ammonium-oxidizing bacteria (AnAOB). Unfortunately, the effects of Cu(Ⅱ) and Ni(Ⅱ) on anammox have not been thoroughly investigated, especially when Cu(Ⅱ) and Ni(Ⅱ) coexist. This work comprehensively investigated the individual and combined effects of Cu(Ⅱ) and Ni(Ⅱ) on anammox and revealed the inhibitory mechanisms. With the influent NH4+-N and NO2−-N concentration of 230 and 250 mg L−1, the inhibition thresholds on anammox are 2.00 mg L−1 Cu(Ⅱ), 1.00 mg L−1 Ni(Ⅱ) and 1.00 mg L−1 Cu(Ⅱ) + 1.00 mg L−1 Ni(Ⅱ), and higher Cu(Ⅱ) or Ni(Ⅱ) concentrations resulted in sharp deteriorations of nitrogen removal performance. The inhibition of Ni(Ⅱ) on anammox was mainly attributed to the adverse effect on NiR activity, while the inhibition mechanism of Cu(Ⅱ) seemed to be unrelated to the four functional enzymes, but associated with disruption of cellular and organellar membranes. The behavior of extracellular polymeric substances (EPS) contributed to the antagonistic effect between Cu(Ⅱ) and Ni(Ⅱ) on anammox. In addition, the niche of Candidatus Brocadia and Candidatus Jettenia shifted under the Cu(II) and Ni(II) stress, and Candidatus Jettenia displayed greater tolerance to Cu(II) and Ni(II) stress. In conclusion, this research clarified the combined effect and the inhibitory mechanism of multiple heavy metals on anammox, and provide the guidances for anammox process application in treating high-ammonium industrial wastewaters containing heavy metals.

Prevalence of COVID-19 Incidence Rates in Hypertension Patients at Ibnu Sina Hospital Makassar in 2020

The COVID-19 virus, which is caused by SARS-CoV-2, is a global health problem that affects many nations. Similar to the H7N9, SARS, and MERS viruses, COVID-19 can be more severe in hypertensive individuals. With a prevalence of 50.1% among COVID-19 patients, hypertension is a significant comorbidity that increases the risk of death by 1.37 times due to the increased number of ACE2 receptors that facilitate the virus's spread. This study uses a descriptive cross-sectional design with secondary data from medical records of COVID-19 patients with hypertension at Rumah Sakit Ibnu Sina Makassar. Data were collected through total sampling after obtaining permission from the hospital and then processed and analyzed descriptively. The study shows that the majority of COVID-19 patients with hypertension are aged 65 and over (33.4%). Male patients are slightly more prevalent (53%) compared to females (47%), possibly due to genetic factors affecting the immune system. Seventy-three percent of patients adhered to hypertension treatment, while 27% did not. The function of the ACE-2 enzyme, which is also affected by antihypertensive treatment, may have an impact on the relationship between COVID-19 and hypertension. These findings emphasize the significance of treating the elderly and remaining on treatment in order to reduce the likelihood of contracting COVID-19. The survey derives that the vast majority of Covid patients with hypertension are developed 65 and over (33.4%), with an insignificantly higher inescapability of folks (53.3%) diverged from females. Adherence to hypertension treatment is high, with 73.3% of patients following their prescribed regimen.

Rationalizing Defective Biomimetic Ceria: In Vitro Demonstration of a Potential “Trojan Horse” Nanozyme Based‐Platform Leveraging Photo‐Redox Activities for Minimally Invasive Therapy

AbstractSemiconductor nanostructures with surface defect‐mediated chemistry have garnered pronounced interest due to their exceptional photo‐induced intracellular bio‐catalytic (enzyme‐mimicking) responses. However, designing defective nanozymes with pH‐responsive multi‐bio‐catalytic functions without any dopants is challenging. Herein, oxygen‐deficient “trojan horse‐like” folate‐functionalized, L‐arginine‐coated ceria (FA‐L‐arg‐CeO2) nanozymes with synergistic multi‐enzyme‐mimicking and anti‐cancer potential are introduced. Intrinsic surface oxygen vacancies (VO●) are strategically created in the nanozymes under kinetically favorable synthesis conditions. Increased surface VO● promotes band structure reconstruction and amplified photochemical‐response efficacy under single laser irradiation (808 nm), outperforming the defect‐free commercial nano‐CeO2 in rapid anti‐tumorigenic activities. Through folate receptor‐mediated endocytosis, these biostable nanozymes localized in MDA‐MB‐231 cells (84% in 48 h) and demonstrated NIR‐accelerated enzymatic functions depending on the pH of the biological milieu. The reduced band gap energy facilitated effective electron‐hole separation, up‐regulating in vitro photo‐redox reactions that impart exceptional therapeutic potential and inhibit 62% cell metastasis within only 12 h. By perturbing intratumoural redox homeostasis, VO●‐rich FA‐L‐arg‐CeO2 nanozymes unanimously killed 86% of MDA‐MB‐231 cancer cells while preferentially shielding benign L929 cells. Transcending beyond conventional drug‐loaded or dopant‐incorporated‐CeO2 nanoplatforms, these defective multi‐modal nanozymes unravel a new avenue for developing smart, low‐cost, bio‐active agents with enhanced efficacy and bio‐safety.

Neuronal extracellular vesicles influence the expression, degradation and oligomeric state of fructose 1,6-bisphosphatase 2 in astrocytes affecting their glycolytic capacity

Fructose 1,6-bisphosphatase 2 (Fbp2) is a regulatory enzyme of gluco- and glyconeogenesis which, in the course of evolution, acquired non-catalytic functions. Fbp2 promotes cell survival during calcium stress, regulates glycolysis via inhibition of Hif-1α activity, and is indispensable for the formation of long-term potentiation in hippocampus. In hippocampal astrocytes, the amount of Fbp2 protein is reduced by signals delivered in neuronal extracellular vesicles (NEVs) through an unknown mechanism. The physiological role of Fbp2 (determined by its subcellular localization/interactions) depends on its oligomeric state and thus, we asked whether the cargo of NEVs is sufficient to change also the ratio of Fbp2 dimer/tetramer and, consequently, influence astrocyte basal metabolism. We found that the NEVs cargo reduced the Fbp2 mRNA level, stimulated the enzyme degradation and affected the cellular titers of different oligomeric forms of Fbp2. This was accompanied with increased glucose uptake and lactate release by astrocytes. Our results revealed that neuronal signals delivered to astrocytes in NEVs provide the necessary balance between enzymatic and non-enzymatic functions of Fbp2, influencing not only its amount but also subcellular localization. This may allow for the metabolic adjustments and ensure protection of mitochondrial membrane potential during the neuronal activity-related increase in astrocytic [Ca2+].

Prostate-Specific Membrane Antigen Biology and Pathophysiology in Prostate Carcinoma, an Update: Potential Implications for Targeted Imaging and Therapy.

Prostate-specific membrane antigen (PSMA), a transmembrane glycoprotein, was shown to be expressed 100-1000 fold higher in prostate adenocarcinoma as compared to normal prostate epithelium. Given the enzymatic function of PSMA with the presence of an internalization triggering motif, various Glu-urea-Lys-based inhibitors have been developed and, amongst others, radiolabeled with positron emitters for targeted positron emission tomography imaging such as 68Ga-PSMA-HBED-CC Glu-urea-Lys(Ahx) as well as with beta and alpha-emitting radioisotopes for targeted therapy, e.g., 177Lu-PSMA-617. In this paper, we review and discuss the potential implications for targeted imaging and therapy of altered PSMA-glycosylation, of PSMA-driven activation of the P13K/Akt/mTOR, of the evolution over time and the relationship with androgen signaling and changes in DNA methylation of PSMA, and of androgen deprivation therapy (ADT) in prostate carcinoma.

Profiling sorghum-microbe interactions with a specialized photoaffinity probe identifies key sorgoleone binders in Acinetobacter pittii.

Interactions between plants and soil microbial communities that benefit plant growth and enhance nutrient acquisition are driven by the selective release of metabolites from plant roots, or root exudation. To investigate these plant-microbe interactions, we developed a photoaffinity probe based on sorgoleone (sorgoleone diazirine alkyne for photoaffinity labeling, SoDA-PAL), a hydrophobic secondary metabolite and allelochemical produced in Sorghum bicolor root exudates. We applied SoDA-PAL to the identification of sorgoleone-binding proteins in Acinetobacter pittii SO1, a potential plant growth-promoting microbe isolated from sorghum rhizosphere soil. Competitive photoaffinity labeling of A. pittii whole cell lysates with SoDA-PAL identified 137 statistically enriched proteins, including putative transporters, transcriptional regulators, and a subset of proteins with predicted enzymatic functions. We performed computational protein modeling and docking with sorgoleone to prioritize candidates for experimental validation and then confirmed binding of sorgoleone to four of these proteins in vitro: the α/β fold hydrolase SrgB (OH685_09420), a fumarylacetoacetase (OH685_02300), a lysophospholipase (OH685_14215), and an unannotated hypothetical protein (OH685_18625). Our application of this specialized sorgoleone-based probe coupled with structural bioinformatics streamlines the identification of microbial proteins involved in metabolite recognition, metabolism, and toxicity, widening our understanding of the range of cellular pathways that can be affected by a plant secondary metabolite.IMPORTANCEHere, we demonstrate that a photoaffinity-based chemical probe modeled after sorgoleone, an important secondary metabolite released by sorghum roots, can be used to identify microbial proteins that directly interact with sorgoleone. We applied this probe to the sorghum-associated bacterium Acinetobacter pittii and showed that probe labeling is dose-dependent and sensitive to competition with purified sorgoleone. Coupling the probe with proteomics and computational analysis facilitated the identification of putative sorgoleone binders, including a protein implicated in a conserved pathway essential for sorgoleone catabolism. We anticipate that discoveries seeded by this workflow will expand our understanding of the molecular mechanisms by which specific metabolites in root exudates shape the sorghum rhizosphere microbiome.

Structure-Guided Identification of Novel Aromatase Inhibitors Targeting Breast Carcinoma.

Aromatase inhibitors play a critical therapeutic role in treating ER+ breast cancer, especially in postmenopausal women. However, their efficacy is often limited by resistance and severe side effects. Identifying new compounds that can disrupt aromatase enzyme function is essential. In this study, structural anomalies in the aromatase enzyme were corrected through energy minimization, and the structure was validated via Ramachandran plot. We screened 170,269 natural compounds from the ASINEX Biodesign library using high-throughput screening algorithms to target the aromatase enzyme. Molecular docking identified three compounds: BDD30170158, BDE33872639, and BDE30177677, all showing stable binding interactions with the aromatase enzyme. Molecular dynamics simulations over 100 ns confirmed the conformational stability of these compounds. Although all three compounds exhibited the desired pharmacokinetic and drug metabolism properties, only one compound (BDE33872639) was identified as a non-blocker, demonstrating a reduced risk of adverse cardiac effects. This compound exhibits significant potential as a novel aromatase inhibitor, warranting further experimental research to develop it as a therapeutic option for ER+ breast cancer.

EnzChemRED, a rich enzyme chemistry relation extraction dataset

Expert curation is essential to capture knowledge of enzyme functions from the scientific literature in FAIR open knowledgebases but cannot keep pace with the rate of new discoveries and new publications. In this work we present EnzChemRED, for Enzyme Chemistry Relation Extraction Dataset, a new training and benchmarking dataset to support the development of Natural Language Processing (NLP) methods such as (large) language models that can assist enzyme curation. EnzChemRED consists of 1,210 expert curated PubMed abstracts where enzymes and the chemical reactions they catalyze are annotated using identifiers from the protein knowledgebase UniProtKB and the chemical ontology ChEBI. We show that fine-tuning language models with EnzChemRED significantly boosts their ability to identify proteins and chemicals in text (86.30% F1 score) and to extract the chemical conversions (86.66% F1 score) and the enzymes that catalyze those conversions (83.79% F1 score). We apply our methods to abstracts at PubMed scale to create a draft map of enzyme functions in literature to guide curation efforts in UniProtKB and the reaction knowledgebase Rhea.

Enhanced peroxidase‐like activity of MnFe2O4 nanoparticles on halloysite nanotubes for uric acid detection

AbstractNanozymes have significantly advanced sensing assays by replicating native enzyme functions. However, designing nanozymes with high catalytic activity and easy recyclability remains challenging. The study presented here has resulted in the development of a highly efficient and sensitive colorimetric system for the detection of uric acid, utilizing MnFe2O4@HNTs—a novel composite material consisting of MnFe2O4 loaded onto halloysite nanotubes. These nanocomposites exhibited outstanding peroxidase‐like activity and attractive magnetic properties. The catalytic efficiency of the MnFe2O4@HNTs in the oxidation of 3,3′,5,5′‐tetramethylbenzidine, in the presence of H2O2, was remarkable, leading to a distinct color change from colorless to blue. A linear relationship was observed between absorbance and UA concentration in the range of 1–20 μM, with a detection limit as low as 52 nM. Mechanistic investigations revealed that reactive oxygen species (ROS), specifically singlet oxygen (1O2), were generated through the decomposition of H2O2, which is responsible for the peroxidase‐like activity demonstrated by the MnFe2O4@HNTs. The method showed minimal interference from serum substances and high selectivity. Magnetic MnFe2O4 allowed easy separation and maintained over 95% activity after seven reuse cycles. The developed assay was successfully applied to the detection of uric acid in human serum, achieving recoveries greater than 98.60%. This research significantly advances the design of recyclable high‐performance nanozymes and establishes an effective colorimetric sensing platform for UA detection in clinical samples, potentially improving diagnostic tools for healthcare applications.

Assessing the effect of high-dose rosuvastatin in elderly patients over 75 with acute coronary syndrome

Backgrounds and objectiveStatins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, are pivotal in managing hypercholesterolemia and reducing cardiovascular risk. While rosuvastatin demonstrates superior efficacy and tolerability compared to other statins, its safety profile in elderly patients older than 75 years old with acute coronary syndrome (ACS) remains underexplored. So, the objective of this study is to evaluate the frequency of adverse reactions and investigate the efficacy of high-dose rosuvastatin on lipid profiles in elderly patients aged over 75 with ACS.MethodsIn this observational study, 110 consecutive elderly ACS patients attending Modarres Hospital in Tehran, Iran, in 2019 were enrolled. The effects of high-dose rosuvastatin were assessed in elderly patients older than 75 years old by comparison of the adverse effects, lipid profile, cardiac function, and other biomarkers at the baseline and after 6 weeks of rosuvastatin therapy with a dose of 40 mg.ResultsFollowing 6 weeks of treatment, there was a significant reduction in total cholesterol (136.2 ± 24.3 to 115.5 ± 24.0, p = 0.001) and LDL levels (72.6 ± 17.5 to 50.9 ± 18.9, p = 0.001), accompanied by a notable increase in HDL levels (38.3 ± 7.1 to 47.2 ± 7.4, p = 0.001). Cardiac function, as measured by ejection fraction (EF), significantly improved from 43.4 ± 8.8 to 48.5 ± 8.5 (p = 0.001). Adverse effects such as cramps (N = 12, p = 0.001), weakness (N = 28, p = 0.001), and anorexia (N = 12, p = 0.001) were reported but did not warrant discontinuation of therapy. Notably, no cases of jaundice were observed. Two deaths occurred due to major adverse cardiac events (MACE) during the study period, unrelated to stroke or recurrent myocardial infarction.ConclusionTotally, high-dose rosuvastatin therapy effectively improved lipid profiles, cardiac function, and liver enzyme levels in elderly ACS patients, with manageable adverse effects. These findings underscore the importance of rosuvastatin in optimizing cardiovascular health in this vulnerable population.

Unraveling the Disulfide-Carbonyl n → π* Interactions in a Gas Phase Molecular Complex and Proteins.

The weak contacts between disulfide linkages and carbonyl groups are anticipated to be important in determining the structure and function of enzymes and proteins. However, the characteristics of the disulfide-carbonyl n → π* (nSS → π* C═O) interactions remain unexplored. Herein, we investigated the nSS → π* C═O interactions in the gas phase and in proteins. Rotational spectroscopic investigation of a model complex of allyl methyl disulfide with formaldehyde identified two structures, both of which are stabilized through a dominant nSS → π* C═O interaction. Surveys of the Protein Data Bank revealed the occurrence of 18 675 nSS → π* C═O interactions associated with 15 320 disulfide bonds in 7105 protein structures. Further theoretical analyses characterize the bonding nature of the nSS → π* C═O interactions. This study provides an in-depth understanding of the stabilizing effect of the nSS → π* C═O interactions in small molecular complexes and biomacromolecules.

3D Variability Analysis Reveals a Hidden Conformational Change Controlling Ammonia Transport in Human Asparagine Synthetase.

How motions in enzymes might be linked to catalytic function is of considerable general interest. Advances in X-ray crystallography and cryogenic electron microscopy (cryo-EM) offer the promise of elucidating functionally relevant conformational changes that are not easily studied by other biophysical methods. Here we use 3D variability analysis (3DVA) of the cryo-EM map for wild-type (WT) human asparagine synthetase (ASNS) to identify a functional role for the Arg-142 side chain as a gate that mediates ammonia access to a catalytically relevant intramolecular tunnel. Our 3DVA-derived hypothesis is assessed experimentally, using the R142I variant in which Arg-142 is replaced by isoleucine, and by molecular dynamics (MD) simulations on independent, computational models of the WT human ASNS monomer and its catalytically relevant, ternary complex with β-aspartyl-AMP and MgPPi. Residue fluctuations in the MD trajectories for the human ASNS monomer are consistent with those determined for 3DVA-derived structures. These MD simulations also indicate that the gating function of Arg-142 is separate from the molecular events that form a continuous tunnel linking the two active sites. Experimental support for Arg-142 playing a role in intramolecular ammonia translocation is provided by the glutamine-dependent synthetase activity of the R142 variant relative to WT ASNS. MD simulations of computational models for the R142I variant and the R142I/β-aspartyl-AMP/MgPPi ternary complex provide a possible molecular basis for this observation. Overall, the combination of 3DVA with MD simulations is a generally applicable approach to generate testable hypotheses of how conformational changes in buried side chains might regulate function in enzymes.