The synergy between Hyaluronic acid (HA) and lipid molecules plays a crucial role in synovial fluids, cell coatings, etc. Diseased cells in cancer and arthritis, show changes in HA concentration and chain size, impacting the viscoelastic and mechanical properties of the cells. Although the solution behavior of HA is known in experiments, a molecular-level understanding of the role of HA on the dynamics at the interface of HA-water and the cellular boundary is lacking. Here we perform atomistic molecular dynamics simulation of short HA chains in explicit water solvent in presence of DPPC bilayer, relevant in pathological cases. We identify a stable interface between HA-water and the bilayer where the water molecules are in contact with the bilayer and the HA chains are located away without any direct contact. Both translation and rotation of the interfacial waters in contact with the lipid bilayer and translation of the HA chains exhibit subdiffusive behavior. The diffusive behavior sets in slightly away from the bilayer, where the diffusion coefficients of water and HA decrease monotonically with increase in HA concentration. On the contrary, the dependence on HA chain size is only marginal due to enhanced chain flexibility as their size increases.
透明质酸（HA）和脂质分子之间的协同作用在滑液、细胞涂层等方面发挥着至关重要的作用。癌症和关节炎中的病变细胞会显示出透明质酸浓度和链大小的变化，从而影响细胞的粘弹性和机械特性。虽然在实验中已知 HA 的溶液行为，但对 HA 在 HA-水界面和细胞边界的动力学作用还缺乏分子层面的了解。在此，我们对在 DPPC 双分子层存在下的显式水溶剂中的短 HA 链进行了原子分子动力学模拟。我们在 HA-水和双分子层之间发现了一个稳定的界面，其中水分子与双分子层接触，而 HA 链则远离双分子层，没有任何直接接触。与脂质双分子层接触的界面水的平移和旋转以及 HA 链的平移都表现出亚扩散行为。扩散行为稍稍远离双分子层，水和 HA 的扩散系数随 HA 浓度的增加而单调降低。相反，由于 HA 链的柔韧性随着其大小的增加而增强，因此与 HA 链大小的关系微乎其微。
{"title":"Dynamics of aqueous suspension of short Hyaluronic acid chains near DPPC bilayer","authors":"Anirban Paul, Jaydeb Chakrabarti","doi":"10.1039/d4cp01088d","DOIUrl":"https://doi.org/10.1039/d4cp01088d","url":null,"abstract":"The synergy between Hyaluronic acid (HA) and lipid molecules plays a crucial role in synovial fluids, cell coatings, etc. Diseased cells in cancer and arthritis, show changes in HA concentration and chain size, impacting the viscoelastic and mechanical properties of the cells. Although the solution behavior of HA is known in experiments, a molecular-level understanding of the role of HA on the dynamics at the interface of HA-water and the cellular boundary is lacking. Here we perform atomistic molecular dynamics simulation of short HA chains in explicit water solvent in presence of DPPC bilayer, relevant in pathological cases. We identify a stable interface between HA-water and the bilayer where the water molecules are in contact with the bilayer and the HA chains are located away without any direct contact. Both translation and rotation of the interfacial waters in contact with the lipid bilayer and translation of the HA chains exhibit subdiffusive behavior. The diffusive behavior sets in slightly away from the bilayer, where the diffusion coefficients of water and HA decrease monotonically with increase in HA concentration. On the contrary, the dependence on HA chain size is only marginal due to enhanced chain flexibility as their size increases.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrzej L. Sobolewski, Magdalena Wioletta Wioletta Duszka, Michal F. Rode
A novel, computationally designed, class of triangular-shape organic molecules with an inverted singlet-triplet (IST) energy gap is investigated with the aid of ab initio methods of electronic structure theory. The considered molecular systems have a form of cyclic oligomers and their common feature is electronic conjugation localized along the molecular rim. Analysis of vertical transition energies from the electronic ground state, as well as from the lowest excited singlet and triplet states of selected molecules, is conducted. The results underscore the significance of optimizing excited-state geometries in theoretical models to accurately describe the optoelectronic properties of the IST molecules, particularly in relation to their applications in OLEDs.
借助电子结构理论的 ab initio 方法，研究了一类通过计算设计的新型三角形有机分子，它们具有倒置的单电子-三电子（IST）能隙。所考虑的分子体系具有环状低聚物的形式，其共同特征是沿分子边缘局部的电子共轭。研究分析了所选分子从电子基态以及最低激发单重态和三重态的垂直转变能量。研究结果强调了在理论模型中优化激发态几何结构的重要性，以准确描述 IST 分子的光电特性，特别是与它们在有机发光二极管中的应用有关的特性。
{"title":"Computational Design of Boron-Free Triangular Molecules with Inverted Singlet-Triplet Energy Gap","authors":"Andrzej L. Sobolewski, Magdalena Wioletta Wioletta Duszka, Michal F. Rode","doi":"10.1039/d4cp01658k","DOIUrl":"https://doi.org/10.1039/d4cp01658k","url":null,"abstract":"A novel, computationally designed, class of triangular-shape organic molecules with an inverted singlet-triplet (IST) energy gap is investigated with the aid of ab initio methods of electronic structure theory. The considered molecular systems have a form of cyclic oligomers and their common feature is electronic conjugation localized along the molecular rim. Analysis of vertical transition energies from the electronic ground state, as well as from the lowest excited singlet and triplet states of selected molecules, is conducted. The results underscore the significance of optimizing excited-state geometries in theoretical models to accurately describe the optoelectronic properties of the IST molecules, particularly in relation to their applications in OLEDs.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the last two decades, numerous pulse sequences have been introduced for the excitation of long-lived spin order (LLS) in high fields. The long continuous wave (CW) or adiabatic pulses used in the SLIC and APSOC sequences should remind one of the spin-locking pulses that are used to induce cross-polarization (CP). Dynamics during these spin-lockings in CP experiments are explained through a geometrical formalism. However, the SLIC and APSOC sequences are described in terms of energy-level picture or in the language of level anti- crossings. Motivated by this analogy, this work presents here a geometrical formalism for the LLS excitation by spin-locking pulses in weakly coupled systems. The formalism is similar to the one used for CP dynamics and reveals new pulse sequences involving CW or adiabatic locking. A similar formalism for the sustaining period of LLS is also provided, which reveals new features of the dynamics and suggests the usage of modulated spin-lockings for proper LLS sustaining. For strong and intermediate regimes, although a simple geometrical formalism seems infeasible, a new pulse sequence that employs a ramp-down adiabatic pulse for both LLS excitation and reconversion to observables in both these regimes is presented here. Given the similarities between LLS excitation and well-developed CP, it may be anticipated that this work would initiate the search for new LLS excitation methods and applications.
{"title":"Excitation of Long-lived Nuclear Spin Order using Spin- locking: A Geometrical Formalism","authors":"Manjeet Mudgil, Narayanan D Kurur","doi":"10.1039/d4cp01995d","DOIUrl":"https://doi.org/10.1039/d4cp01995d","url":null,"abstract":"Over the last two decades, numerous pulse sequences have been introduced for the excitation of long-lived spin order (LLS) in high fields. The long continuous wave (CW) or adiabatic pulses used in the SLIC and APSOC sequences should remind one of the spin-locking pulses that are used to induce cross-polarization (CP). Dynamics during these spin-lockings in CP experiments are explained through a geometrical formalism. However, the SLIC and APSOC sequences are described in terms of energy-level picture or in the language of level anti- crossings. Motivated by this analogy, this work presents here a geometrical formalism for the LLS excitation by spin-locking pulses in weakly coupled systems. The formalism is similar to the one used for CP dynamics and reveals new pulse sequences involving CW or adiabatic locking. A similar formalism for the sustaining period of LLS is also provided, which reveals new features of the dynamics and suggests the usage of modulated spin-lockings for proper LLS sustaining. For strong and intermediate regimes, although a simple geometrical formalism seems infeasible, a new pulse sequence that employs a ramp-down adiabatic pulse for both LLS excitation and reconversion to observables in both these regimes is presented here. Given the similarities between LLS excitation and well-developed CP, it may be anticipated that this work would initiate the search for new LLS excitation methods and applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated emissive urea compounds with an anthryl moiety on one side and a substituent group (biphenyl, naphthyl, benzyl, or cyclohexyl) on the other side across from the urea group. This was performed to determine the contribution of π-conjugation on a substituent group to excited-state intermolecular proton-transfer (ESPT) reactions in the presence of acetate anions. Fluorescence lifetime measurements revealed that the rate constant of the ESPT reaction from the normal form to the tautomer form increased with the length of the π-conjugation. Considering that there were a few differences among the wavelengths of the fluorescence maxima for the anthracene–urea derivatives in the presence of acetate anions, we observed that the extension of π-conjugation promoted tautomer formation. This maintained the energy levels of the normal and tautomer forms in the excited state. Furthermore, an anthracene–urea derivative without π-conjugation did not undergo a reverse ESPT reaction, implying that π-conjugation is considerably involved in the reverse ESPT reaction from the tautomer form to the normal form.
{"title":"π-conjugation effects on excited-state intermolecular proton-transfer reactions of anthracene–urea derivatives in the presence of acetate anions","authors":"Atsushi Tachibanaki, Toru Matsui, Yoshinobu Nishimura","doi":"10.1039/d4cp01869a","DOIUrl":"https://doi.org/10.1039/d4cp01869a","url":null,"abstract":"This study investigated emissive urea compounds with an anthryl moiety on one side and a substituent group (biphenyl, naphthyl, benzyl, or cyclohexyl) on the other side across from the urea group. This was performed to determine the contribution of π-conjugation on a substituent group to excited-state intermolecular proton-transfer (ESPT) reactions in the presence of acetate anions. Fluorescence lifetime measurements revealed that the rate constant of the ESPT reaction from the normal form to the tautomer form increased with the length of the π-conjugation. Considering that there were a few differences among the wavelengths of the fluorescence maxima for the anthracene–urea derivatives in the presence of acetate anions, we observed that the extension of π-conjugation promoted tautomer formation. This maintained the energy levels of the normal and tautomer forms in the excited state. Furthermore, an anthracene–urea derivative without π-conjugation did not undergo a reverse ESPT reaction, implying that π-conjugation is considerably involved in the reverse ESPT reaction from the tautomer form to the normal form.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grain boundaries (Gb) in transition metal dichalcogenides are a rich source of interesting physics in their vicinity as well as a cause of concern for large area electronic device applications. Here, using first principles calculations we show a non-monotonic correlation between the grain misorientation and the local bandgap. The internal defect structure is seen to be the key differentiator and we observe that even the standard 5-7 defect ring in the 2D Gb exhibits differing characteristics based on its internal configuration explaining many experimental anomalies. While the 5-7 ring presents shallow defect states, long range strain fields with a significant increment in the local bandgap, the other commonly observed 4-8 defect rings introduce only mid-gap states, smaller strain fields, with no observable bandgap change. The results show the seminal character of the individual defect structures, and their relative density determines the overall physio-chemical property of the grain boundary.
{"title":"Defect Structure-Electronic Property Correlations in Transition Metal Dichalcogenide Grain boundaries","authors":"Srest Somay, Krishna Balasubramanian","doi":"10.1039/d4cp00959b","DOIUrl":"https://doi.org/10.1039/d4cp00959b","url":null,"abstract":"Grain boundaries (Gb) in transition metal dichalcogenides are a rich source of interesting physics in their vicinity as well as a cause of concern for large area electronic device applications. Here, using first principles calculations we show a non-monotonic correlation between the grain misorientation and the local bandgap. The internal defect structure is seen to be the key differentiator and we observe that even the standard 5-7 defect ring in the 2D Gb exhibits differing characteristics based on its internal configuration explaining many experimental anomalies. While the 5-7 ring presents shallow defect states, long range strain fields with a significant increment in the local bandgap, the other commonly observed 4-8 defect rings introduce only mid-gap states, smaller strain fields, with no observable bandgap change. The results show the seminal character of the individual defect structures, and their relative density determines the overall physio-chemical property of the grain boundary.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The involvement of p53 aggregation in cancer pathogenesis emphasizes the importance of unraveling the mechanisms underlying mutation-induced p53 destabilization. And understanding how small molecule inhibitors prevent the conversion of p53 into aggregation-primed conformations is pivotal for the development of therapeutics targeting p53-aggregation-associated cancers. A recent experimental study highlights the efficacy of the proteomimetic amyloid inhibitor ADH-6 in stabilizing R248W p53 and inhibiting its aggregation in cancer cells by interacting with p53 core domain (p53C). However, it remains mostly unclear how R248W mutation induces destabilization of the p53C and how ADH-6 stabilizes this p53C mutant and inhibits its aggregation. Herein, we conducted all-atom molecular dynamics simulations on R248W p53C in the absence and presence of ADH-6, as well as wild-type (WT) p53C. Our simulations reveal that the R248W mutation results in a shift of helix H2 and β-hairpin S2-S2' towards the mutation site, leading to the destruction of their neighboring β-sheet structure. This further facilitates the formation of a cavity in the hydrophobic core, and reduces the stability of the β-sandwich. Importantly, two crucial aggregation-prone regions (APRs) S9 and S10 are disturbed and more exposed to solvent in the R248W p53C, which is conducive to p53C aggregation. Intriguingly, ADH-6 dynamically binds to the mutation site and multiple destabilized regions in R248W p53C, partially inhibiting the shift of helix H2 and β-hairpin S2-S2', thus preventing the disruption of the β-sheets and the formation of the cavity. ADH-6 also reduces solvent exposure of APRs S9 and S10, which disfavors the aggregation of R248W p53C. Moreover, ADH-6 can preserve the WT-like dynamical network of R248W p53C. Our study elucidates the mechanisms underlying the oncogenic R248W mutation induced p53C destabilization and the structural protection of p53C by ADH-6.
{"title":"Oncogenic R248W mutation induced conformational perturbation of p53 core domain and the structural protection by proteomimetic amyloid inhibitor ADH-6","authors":"Qian Liu, yawei Yu, Guanghong Wei","doi":"10.1039/d4cp02046d","DOIUrl":"https://doi.org/10.1039/d4cp02046d","url":null,"abstract":"The involvement of p53 aggregation in cancer pathogenesis emphasizes the importance of unraveling the mechanisms underlying mutation-induced p53 destabilization. And understanding how small molecule inhibitors prevent the conversion of p53 into aggregation-primed conformations is pivotal for the development of therapeutics targeting p53-aggregation-associated cancers. A recent experimental study highlights the efficacy of the proteomimetic amyloid inhibitor ADH-6 in stabilizing R248W p53 and inhibiting its aggregation in cancer cells by interacting with p53 core domain (p53C). However, it remains mostly unclear how R248W mutation induces destabilization of the p53C and how ADH-6 stabilizes this p53C mutant and inhibits its aggregation. Herein, we conducted all-atom molecular dynamics simulations on R248W p53C in the absence and presence of ADH-6, as well as wild-type (WT) p53C. Our simulations reveal that the R248W mutation results in a shift of helix H2 and β-hairpin S2-S2' towards the mutation site, leading to the destruction of their neighboring β-sheet structure. This further facilitates the formation of a cavity in the hydrophobic core, and reduces the stability of the β-sandwich. Importantly, two crucial aggregation-prone regions (APRs) S9 and S10 are disturbed and more exposed to solvent in the R248W p53C, which is conducive to p53C aggregation. Intriguingly, ADH-6 dynamically binds to the mutation site and multiple destabilized regions in R248W p53C, partially inhibiting the shift of helix H2 and β-hairpin S2-S2', thus preventing the disruption of the β-sheets and the formation of the cavity. ADH-6 also reduces solvent exposure of APRs S9 and S10, which disfavors the aggregation of R248W p53C. Moreover, ADH-6 can preserve the WT-like dynamical network of R248W p53C. Our study elucidates the mechanisms underlying the oncogenic R248W mutation induced p53C destabilization and the structural protection of p53C by ADH-6.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lukáš Tomaník, Michele Pugini, Karen Mudryk, Stephan Thürmer, Dominik Stemer, Bruno BC Credidio, Florian Trinter, Bernd Winter, Petr Slavicek
Liquid-jet photoemission spectroscopy (LJ-PES) directly probes the electronic structure of solutes and solvents. It also emerges as a novel tool to explore chemical structure in aqueous solutions, yet the scope of the approach has to be examined. Here, we present a pH-dependent liquid-jet photoelectron spectroscopic investigation of ascorbic acid (vitamin C). We combine core-level photoelectron spectroscopy and ab initio calculations, allowing us to site-specifically explore the acid-base chemistry of the biomolecule. For the first time, we demonstrate the capability of the method to simultaneously assign two deprotonation sites within the molecule. We show that a large change in chemical shift appears even for atoms distant several bonds from the chemically modified group. Furthermore, we present a highly efficient and accurate computational protocol based on a single structure using the maximum overlap method for modeling core-level photoelectron spectra in aqueous environments. This work poses a broader question: To what extent can LJ-PES complement established structural techniques such as nuclear magnetic resonance? Answering this question is highly relevant in view of the large number of incorrect molecular structures published.
液体喷射光发射光谱（LJ-PES）可直接探测溶质和溶剂的电子结构。它也是探索水溶液中化学结构的一种新工具，但这种方法的适用范围还有待研究。在此，我们介绍了抗坏血酸（维生素 C）的 pH 值依赖性液体喷射光电子能谱研究。我们结合了核心级光电子能谱和 ab initio 计算，从而能够针对特定位点探索生物大分子的酸碱化学性质。我们首次展示了该方法同时分配分子内两个去质子化位点的能力。我们表明，即使是与化学修饰基团相距几个键的原子，其化学位移也会发生很大变化。此外，我们还介绍了一种基于单一结构的高效、精确计算方案，该方案使用最大重叠法对水环境中的核心级光电子能谱进行建模。这项工作提出了一个更广泛的问题：LJ-PES 能在多大程度上对核磁共振等成熟的结构技术起到补充作用？鉴于已发表的大量错误分子结构，回答这一问题具有重要意义。
{"title":"Liquid-Jet Photoemission Spectroscopy as a Structural Tool: Site-Specific Acid-Base Chemistry of Vitamin C","authors":"Lukáš Tomaník, Michele Pugini, Karen Mudryk, Stephan Thürmer, Dominik Stemer, Bruno BC Credidio, Florian Trinter, Bernd Winter, Petr Slavicek","doi":"10.1039/d4cp01521e","DOIUrl":"https://doi.org/10.1039/d4cp01521e","url":null,"abstract":"Liquid-jet photoemission spectroscopy (LJ-PES) directly probes the electronic structure of solutes and solvents. It also emerges as a novel tool to explore chemical structure in aqueous solutions, yet the scope of the approach has to be examined. Here, we present a pH-dependent liquid-jet photoelectron spectroscopic investigation of ascorbic acid (vitamin C). We combine core-level photoelectron spectroscopy and ab initio calculations, allowing us to site-specifically explore the acid-base chemistry of the biomolecule. For the first time, we demonstrate the capability of the method to simultaneously assign two deprotonation sites within the molecule. We show that a large change in chemical shift appears even for atoms distant several bonds from the chemically modified group. Furthermore, we present a highly efficient and accurate computational protocol based on a single structure using the maximum overlap method for modeling core-level photoelectron spectra in aqueous environments. This work poses a broader question: To what extent can LJ-PES complement established structural techniques such as nuclear magnetic resonance? Answering this question is highly relevant in view of the large number of incorrect molecular structures published.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Limited availability of photogenerated charge carriers in two-dimensional (2D) materials, due to high exciton binding energies, is a major bottleneck in achieving efficient photocatalytic water splitting (PWS). Strong excitonic effects in 2D materials demand precise attention to electron-electron correlation, electron-hole interaction and electron-phonon coupling simultaneously. In this work, we explore the temperature-dependent electronic and optical responses of an efficient photocatalyst, blue-AsP (β-AsP), by integrating electron-phonon coupling into state-of-the-art GW+BSE calculations. Interestingly, strong electron-lattice interaction at high temperature promotes photocatalytic water splitting with the increasing supply of long-lived dark excitons. This work presents an atypical observation contrary to the general assumption that only bright excitons enhance the PWS due to prominent absorption. Dark excitons due to the low recombination rate, exhibit long-lived photogenerated electron-hole pairs with high exciton lifetime increasing with temperature up to ~0.25 μs.
{"title":"Temperature-Driven Journey of Dark Excitons to Efficient Photocatalytic Water Splitting in β-AsP","authors":"Harshita Seksaria, Amal Kishore, Abir De Sarkar","doi":"10.1039/d4cp01937g","DOIUrl":"https://doi.org/10.1039/d4cp01937g","url":null,"abstract":"Limited availability of photogenerated charge carriers in two-dimensional (2D) materials, due to high exciton binding energies, is a major bottleneck in achieving efficient photocatalytic water splitting (PWS). Strong excitonic effects in 2D materials demand precise attention to electron-electron correlation, electron-hole interaction and electron-phonon coupling simultaneously. In this work, we explore the temperature-dependent electronic and optical responses of an efficient photocatalyst, blue-AsP (β-AsP), by integrating electron-phonon coupling into state-of-the-art GW+BSE calculations. Interestingly, strong electron-lattice interaction at high temperature promotes photocatalytic water splitting with the increasing supply of long-lived dark excitons. This work presents an atypical observation contrary to the general assumption that only bright excitons enhance the PWS due to prominent absorption. Dark excitons due to the low recombination rate, exhibit long-lived photogenerated electron-hole pairs with high exciton lifetime increasing with temperature up to ~0.25 μs.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isocitrate dehydrogenase 2 (IDH2) is a homodimeric enzyme that plays an important role in energy production. A mutation R140Q in one monomer makes the enzyme tumourigenic. Enasidenib is an effective inhibitor of IDH2/R140Q. A secondary mutation Q316E leads to enasidenib resistance. This mutation was hitherto only found in trans, i.e. where one monomer has the R140Q mutation and the other carries the Q316E mutation. It is not clear if the mutation only leads to resistance when in trans or if it has been discovered in {em trans} only by chance, since it was only reported in two patients. Using molecular dynamics (MD) simulations we show that the binding of enasidenib to IDH2 is indeed much weaker when the Q316E mutation takes place in trans not in cis, which provides a molecular explanation for the clinical finding. This is corroborated by non-covalent interaction (NCI) analysis and DFT calculations. Whereas the MD simulations show a loss of one hydrogen bond upon the resistance mutation, NCI and energy decomposition analysis (EDA) reveal that a multitude of interactions are weakened.
{"title":"Trans vs Cis: A Computational Study of Enasidenib Resistance due to IDH2 Mutations","authors":"Erik Lindahl, Erik Arvidsson, Ran Friedman","doi":"10.1039/d4cp01571a","DOIUrl":"https://doi.org/10.1039/d4cp01571a","url":null,"abstract":"Isocitrate dehydrogenase 2 (IDH2) is a homodimeric enzyme that plays an important role in energy production. A mutation R140Q in one monomer makes the enzyme tumourigenic. Enasidenib is an effective inhibitor of IDH2/R140Q. A secondary mutation Q316E leads to enasidenib resistance. This mutation was hitherto only found in trans, i.e. where one monomer has the R140Q mutation and the other carries the Q316E mutation. It is not clear if the mutation only leads to resistance when in trans or if it has been discovered in {em trans} only by chance, since it was only reported in two patients. Using molecular dynamics (MD) simulations we show that the binding of enasidenib to IDH2 is indeed much weaker when the Q316E mutation takes place in trans not in cis, which provides a molecular explanation for the clinical finding. This is corroborated by non-covalent interaction (NCI) analysis and DFT calculations. Whereas the MD simulations show a loss of one hydrogen bond upon the resistance mutation, NCI and energy decomposition analysis (EDA) reveal that a multitude of interactions are weakened.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ying Ma, Fan Tang, Ziyi Liu, Junqing Li, Haowei Wang, Fan Wu Fan, Dongqi Wang, An-Hui Lu
Rational design of γ-alumina-based catalysts relies on an extensive understanding of the distribution of hydroxyl groups on the surface of γ-alumina and their physicochemical properties, which remain unclear and challenging to determine experimentally due to the structural complexity. In this work, by means of DFT and thermodynamic calculations, various hydroxylation modes of γ-alumina (110) and (100) surfaces at different OH coverages were evaluated, based on which a thermodynamic model to reflect the relation between temperature and surface structure was established and the stable hydroxylation modes under experimental conditions were predicted. This enables us to identify the experimentally measured IR spectra. The effect of hydroxyl coverages on the surface Lewis acidity was then analyzed, and showed that the presence of hydroxyl groups could promote the Lewis acidity of neighboring Al sites. This work provides fundamental insights on molecular level understanding of the surface properties of γ-alumina and benefits the rational design of alumina-based catalysts.
{"title":"A Thermodynamic Model of the Surface Hydroxylation of γ-Al2O3","authors":"ying Ma, Fan Tang, Ziyi Liu, Junqing Li, Haowei Wang, Fan Wu Fan, Dongqi Wang, An-Hui Lu","doi":"10.1039/d4cp01968g","DOIUrl":"https://doi.org/10.1039/d4cp01968g","url":null,"abstract":"Rational design of γ-alumina-based catalysts relies on an extensive understanding of the distribution of hydroxyl groups on the surface of γ-alumina and their physicochemical properties, which remain unclear and challenging to determine experimentally due to the structural complexity. In this work, by means of DFT and thermodynamic calculations, various hydroxylation modes of γ-alumina (110) and (100) surfaces at different OH coverages were evaluated, based on which a thermodynamic model to reflect the relation between temperature and surface structure was established and the stable hydroxylation modes under experimental conditions were predicted. This enables us to identify the experimentally measured IR spectra. The effect of hydroxyl coverages on the surface Lewis acidity was then analyzed, and showed that the presence of hydroxyl groups could promote the Lewis acidity of neighboring Al sites. This work provides fundamental insights on molecular level understanding of the surface properties of γ-alumina and benefits the rational design of alumina-based catalysts.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：