ACS Physical Chemistry Au最新文献

{"title":"Role of Small Membrane Proteins in the Green Sulfur Bacterial Reaction Center","authors":"Alexandros Lyratzakis,&nbsp;Ariadni Konstantopoulou,&nbsp;Evangelia-Vasiliki Fragkaki,&nbsp;Theofani-Iosifina Sousani,&nbsp;Ilias G. Karvounis,&nbsp;Georgios Tsiotis,&nbsp;Vangelis Daskalakis","doi":"10.1021/acsphyschemau.5c00142","DOIUrl":"10.1021/acsphyschemau.5c00142","url":null,"abstract":"<p>The highly efficientlight-driven energy conversion in large biologicalcomplexes, such as the Photosynthetic Reaction Center (RC) of greensulfur bacteria (GSB), relies on precisely tuned protein dynamicsand intersubunit communication. Small membrane proteins are criticalregulators of this efficiency; yet, their mechanistic roles in dictatingphotophysical and electron transfer properties remain largely elusive.We leverage atomistic molecular dynamics (MD) simulations integratedwith advanced Graph Network Analysis tools to uncover the functionalsignificance of two peripheral subunits, PscE and PscF, on the GSBRC complex. These subunits occupy critical interfacial positions thatdynamically regulate the complex’s architecture. PscE formsa persistent interaction with PscC, exerting a steric influence ona PscA core helix. In parallel, the peripheral PscE–PscF pairmodulates the coupling between PscC and the P₈₄₀ specialpair, suggesting a dynamic mechanism for fine-tuning electron transferefficiency. Our findings are consistent with cryogenic electron microscopy(Cryo-EM) electron densities and establish small auxiliary subunitsas integral mechanical components that control long-range allostericcommunication, providing atomic-level insight into optimizing energyconversion in natural photosystems.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"462–474"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decarboxylation via a Higher Electronic Excited State Drives LSSmOrange Photoconversion","authors":"Hyang Sook Seol,&nbsp;Fangjia Luo,&nbsp;Elke De Zitter,&nbsp;Nipawan Nuemket,&nbsp;Eduard Fron,&nbsp;Neil R. McFarlane,&nbsp;Leonie De Vrieze,&nbsp;Janko Civic,&nbsp;Michiel Postelmans,&nbsp;Savannah Van Bel,&nbsp;Shigeki Owada,&nbsp;Kensuke Tono,&nbsp;Tomoyuki Tanaka,&nbsp;Toshi Arima,&nbsp;Hiroki Noguchi,&nbsp;Thi Yen Hang Bui,&nbsp;Rie Tanaka,&nbsp;Kazuya Hasegawa,&nbsp;Kunio Hirata,&nbsp;Dohyun Im,&nbsp;Tsuyoshi Araya,&nbsp;Tetsunari Kimura,&nbsp;Luc Van Meervelt,&nbsp;Martin Weik,&nbsp;Jeremy N. Harvey,&nbsp;Jacques-Philippe Colletier,&nbsp;So Iwata,&nbsp;Eriko Nango,&nbsp;Hideaki Mizuno","doi":"10.1021/acsphyschemau.6c00009","DOIUrl":"10.1021/acsphyschemau.6c00009","url":null,"abstract":"<p>LSSmOrange is a fluorescent protein thatexhibits slowphotoconversionand is used as an imaging tool to highlight specific subpopulationsof molecules. While photoconversion in LSSmOrange is known to involveKolbe decarboxylation of the E215 side chain, its structural dynamicsremain unexplored. We addressed the excited state dynamics of LSSmOrangeby using serial femtosecond crystallography (SFX) with an X-ray freeelectron laser. SFX enabled us to determine the crystal structureof unconverted LSSmOrange without detectable X-ray damage, facilitatinga femtosecond optical pump─X-ray probe experiment to tracktime-resolved structural changes. A decrease in electron density atE215 was observed 250 ps after strong pump laser illumination (meanfluence of 0.31 J/cm²), consistent with photoconversionby decarboxylation. Extrapolated structures suggested the appearanceof an alternative E215 conformation in addition to illumination-induceddecarboxylation. Since the photoinduced decarboxylation occurred despitethe extremely low single-photon photoconversion quantum yield of LSSmOrange(8.5 × 10^–6), we hypothesized that the photoconversionproceeds via a multiphoton process. Power titration using transientabsorption spectroscopy revealed that photoconversion was linked tooptical nonlinearity under a high pump laser energy. We propose thatLSSmOrange photoconversion involves a higher-lying electronic excitedstate triggered by multiphoton absorption, as supported by quantum-chemicalcalculations. Photoconversion via a multiphoton process enables spatiallyconfined highlighting on a microscope.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"534–551"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anion-Dependent Redox Pathways Governing Water Splitting in Superconcentrated Lithium Electrolytes","authors":"Sagar Ingavale,&nbsp;Pawin Iamprasertkun","doi":"10.1021/acsphyschemau.6c00037","DOIUrl":"10.1021/acsphyschemau.6c00037","url":null,"abstract":"<p>Electrochemistry involving superconcentrated electrolyteshas rapidlygained attention as a transformative approach in electrochemical processes.Superconcentrated electrolytes have emerged as a groundbreaking solutionin electrochemical applications, recognized for their nonflammablenature, ecofriendly composition, and expanded electrochemical stabilitywindow compared to conventional dilute aqueous electrolytes. The electrochemicalhydrogen evolution reaction (HER) and oxygen evolution reaction (OER)are fundamental processes in energy conversion and storage technologies.This study investigates the electrochemical activity of platinum electrodesin lithium-based electrolytes for understanding the electrochemicalcharacteristics from low to high concentration. The HER and OER kineticsin superconcentrated electrolytes were performed to address challengesrelated to stability and efficiency in high-concentration ionic environments.Highly concentrated electrolytes characterized by their unique solvationstructure and extended electrochemical stability potential windowoffer promising avenues for enhancing energy storage and conversionapplications. Through cyclic voltammetry and linear sweep voltammetry,we analyze key parameters such as redox reactions, overpotentials,and kinetic reactions. This study explores the interaction betweenplatinum and highly concentrated aqueous electrolytes to elucidateits influence on catalytic performance. The results provide insightsinto optimizing platinum-based electrocatalysis for next-generationsustainable energy solutions, highlighting the role of electrolytecomposition in dictating reaction kinetics, potential window, andoverall electrochemical performance.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"425–434"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amide Hydrogen–Deuterium Exchange in Isotopically Mixed Water","authors":"Antonio Grimaldi,&nbsp;Billy Hobbs,&nbsp;Michele Stofella,&nbsp;Theodoros K. Karamanos,&nbsp;Emanuele Paci","doi":"10.1021/acsphyschemau.5c00127","DOIUrl":"10.1021/acsphyschemau.5c00127","url":null,"abstract":"<p>Hydrogen–deuterium exchange (HDX) of protein backboneamidesprovides a powerful probe of conformational dynamics. However, whenexperiments are performed in H₂O/D₂O mixtures,quantitative interpretation is hindered by back exchange and isotopeeffects not captured by the classical Linderstro̷m–Lang(LL) model. We introduce a generalized Linderstro̷m–Lang(GLL) framework that explicitly accounts for forward and reverse exchangeand for changes in protection upon isotopic substitution. Analyticalsolutions describe equilibrium enrichment (fractionation) and protectionfactors in mixtures, reducing to the LL model in pure D₂O. Application to HDX/NMR of the molecular chaperone DNAJB1 in 50%D₂O demonstrates that the GLL model recovers protectionfactors at 100% D₂O. Ignoring back exchange (i.e., usingthe LL model), protection factors are systematically underestimated.A particularly powerful feature of our approach is that a single HDXexperiment in a mixture (e.g., 50% D₂O) simultaneouslyprovides protection factors that report on conformational dynamicsand local stability and fractionation factors that are sensitive tothe local hydrogen-bonding environment.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"446–450"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scanning Tunneling Microscope-Based Break-Junction Technique─A Tutorial","authors":"Emma York,&nbsp;Latha Venkataraman","doi":"10.1021/acsphyschemau.6c00026","DOIUrl":"10.1021/acsphyschemau.6c00026","url":null,"abstract":"<p>Over the past two decades, molecular electronics hasmade significantprogress toward discovering nanoscale analogues of conventional electroniccomponents, largely enabled by the development of the scanning tunnelingmicroscope-based break-junction (STM-BJ) technique. The STM-BJ techniqueenables precise and highly reproducible measurement of a molecule’selectronic transport properties, making it a powerful technique toexplore physiochemical and electrochemical phenomena that are otherwisedifficult to access. It has gained substantial popularity in the past20 years, with experiments becoming increasingly diverse and sophisticated.Despite the wealth of literature, an accessible, practical guide toperforming STM-BJ experiments and interpreting the data is largelyabsent. This tutorial includes a brief background into the developmentof STM-BJ measurements, followed by detailed explanations of instrumentation,data collection, statistical analysis, variations on standard experiments,and some troubleshooting methods. It is aimed at researchers lookingto begin or improve STM-BJ studies in their laboratories, graduatestudents and postdoctoral researchers learning the technique, andreaders seeking to critically evaluate the growing body of STM-BJliterature.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"408–424"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free-Energy Profiles of Confined Reactions: Influence of Confinement Type and Challenges for Metadynamics Methods","authors":"Michelle Ernst,&nbsp;Jürg Hutter","doi":"10.1021/acsphyschemau.5c00151","DOIUrl":"10.1021/acsphyschemau.5c00151","url":null,"abstract":"<p>Metadynamics enables the reconstruction of free-energysurfacesfrom molecular dynamics; however, its application is often challengingbecause numerous methodological choices can influence the results.Here, we focus on how geometric confinement reshapes reactant andproduct basins and thereby contributes to catalytic effects. Our analysisis based on two prototypical reactions: a symmetric S_N2fluorine-substitution reaction, CH₃F + F^–<em>⇌</em> F^– + CH₃Fand a Diels–Alder cycloaddition. We compare several metadynamicsapproaches: well-tempered metadynamics, on-the-fly probability-enhancedsampling (OPES), OPES-Explore, and a hybrid OPES + OPES-Explore scheme,and we examine two types of confinements: First, we analyze the influenceof methodological confinement introduced by restraining walls, a commonlyused but seldom assessed component of enhanced sampling simulations.Second, we examine chemical confinement inside carbon nanotubes ofvarying diameters. We find that the restraining wall does not alterthe activation free energy of the studied reactions but significantlyaffects the widths of the reactant and product basins. In contrast,confinement inside carbon nanotubes changes the barrier height byenforcing axial alignment of the reactants in the S_N2 reactionand by restricting the transition-state and product geometries inthe Diels–Alder case. Concerning the metadynamics methods,we found different convergence behavior and sampling quality, evenfor these simple reactions. The results highlight how both physicaland methodological confinement can influence the outcome of enhanced-samplingsimulations, and they underscore the need for careful choice of metadynamicsmethods for reactions in restricted environments.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"493–502"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of Charge Resonances in the Benzene Dimer","authors":"Alice Balbi,&nbsp;Andrea Rygg Aagaard,&nbsp;Sarai Dery Folkestad,&nbsp;Ida-Marie Høyvik","doi":"10.1021/acsphyschemau.5c00149","DOIUrl":"10.1021/acsphyschemau.5c00149","url":null,"abstract":"<p>Modern electronic-structuretheory defines dispersioninteractionsas connected intramonomer excitations. Using this definition, dispersioncontributions have been shown in literature to be large relative toother contributions at van der Waals distances for the ground statebenzene dimer. However, are the dispersion contributions sufficientto describe its potential energy surface? In this paper, we show theimportance of charge resonances for the shape of the potential energysurface of the stacked benzene dimer. Charge resonances is a colloquialterm for the presence of ion-pair configurations in the electronicwave function, and they represent a charge delocalization betweenthe benzene molecules. We show that the ion-pair configurations, generatedfrom connected intra and intermonomer excitations, have a significantimpact on the potential energy curves as functions of parallel displacement,as well as intramonomer separation. For parallel displacement, theenergy minimum shifts approximately 2 Å toward greater displacementif ion-pair configurations are not included. Hence, to understandthe noncovalent bonding in the benzene dimer two mechanisms must betaken into account: dispersion interaction and charge resonances.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"475–482"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noncovalent Catalysis of Renewable Chitosan Biopolymer for the Conversion of CO2 to Green Urea for Sustainable Agriculture","authors":"Abdul Hamid Malhan,&nbsp;Rudharachari Parameshwari,&nbsp;Krishnan Thirumoorthy","doi":"10.1021/acsphyschemau.6c00008","DOIUrl":"10.1021/acsphyschemau.6c00008","url":null,"abstract":"<p>The present studyemploys density functional theory to investigatethe noncovalent catalysis by chitosan for the conversion of CO₂ and NH₃ to urea, addressing the pressing needfor carbon capture and utilization by converting captured CO₂ from industrial sources into a renewable C1 feedstock, specificallyurea, which is known for its high nitrogen content as a fertilizer.The conversion of CO₂ into urea is crucial to modern agriculture,providing a highly efficient and cost-effective means of supplyingthe nitrogen required to nourish the global population. Computationalquantum chemical calculations elucidate the reaction mechanism, detailingall relevant intermediates and transition states. The findings revealthat the NH₂ and OH functional groups of chitosan playa critical role in the reaction by stabilizing key transition statesthrough noncovalent interactions, thereby substantially lowering theoverall activation energy barrier. The current study provides significantmolecular-level insights into the mechanism underlying chitosan’snoncovalent catalytic properties, establishing a robust foundationfor understanding its potential applications as an effective, environmentallysustainable approach to urea synthesis. This work marks a significantadvancement in green catalysis, aligning with UN Sustainable DevelopmentGoals (SDG) 13 (Climate Action) by using CO₂ as a feedstock,SDG 9 (Industry, Innovation, and Infrastructure) by providing a sustainableindustrial alternative, and SDG 12 (Responsible Consumption and Production)by demonstrating a circular-economy model valorizing biowaste. Thesefindings pave the way for future experimental validation and the developmentof biopolymer catalysts, contributing to a more sustainable chemicalindustry.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"527–533"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Seasons of a Career in Physical Chemistry","authors":"Gemma C. Solomon,&nbsp;Joan-Emma Shea,&nbsp;Gregory D. Scholes","doi":"10.1021/acsphyschemau.6c00078","DOIUrl":"10.1021/acsphyschemau.6c00078","url":null,"abstract":"","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"388–388"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomistic Simulation of Collapse and Recrystallization in Hollow Gold and Silver Nanoparticles with Ultrathin, Porous Walls","authors":"Vladimir S. Myasnichenko,&nbsp;Denis Sokolov,&nbsp;Anatolii Bazulev,&nbsp;Kseniya Savina,&nbsp;Oleg Polev,&nbsp;Valentin Romanovski,&nbsp;Nickolay Sdobnyakov","doi":"10.1021/acsphyschemau.6c00001","DOIUrl":"10.1021/acsphyschemau.6c00001","url":null,"abstract":"<p>Understanding thethermal stability of hollow metal nanoframesremains a significant challenge due to strongly coupled effects suchas porosity, curvature, and defect migration. Using tight-bindingMonte Carlo simulations, we systematically investigate gold and silvernanoframes with cavity radii of 7.0–19.9 Å and quantitativelyresolve their structural evolution through a shape-parametrizationmethod that tracks cavity collapse and global flattening with ångström-levelprecision. Silver nanoframes exhibit lateral pore closure at 605–785K, cavity collapse at 783–844 K, and melting near 852–900K. Gold analogues show earlier pore closure (585–720 K) buthigher collapse temperatures (688–823 K) and melting at 772–825K, consistent with more coordinated recrystallization. The flatteningparameter rises to 0.18–0.22 before global deformation, servingas a universal geometric indicator. Together, these quantitative criteriaadvance mechanistic understanding and enable the predictive designof thermally robust porous metal nanostructures.</p>","PeriodicalId":29796,"journal":{"name":"ACS Physical Chemistry Au","volume":"6 3","pages":"514–526"},"PeriodicalIF":4.8,"publicationDate":"2026-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148139141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}