Molecular dynamics simulation of the effect of temperature on the conformation of ubiquitin protein.

Content: Ubiquitin, a ubiquitous small protein found in all living organisms, is crucial for tagging proteins earmarked for degradation and holds pivotal importance in biomedicine. Protein functionality is intricately linked to its structure. To comprehend the impact of diverse temperatures on ubiquitin protein structure, our study delved into the energy landscape, hydrogen bonding, and overall structural stability of ubiquitin protein at varying temperatures.

Density Functional Theory Study of CO Hydrogenation on Transition-Metal-Doped Cu(211) Surfaces.

The massive emission of CO has caused a series of environmental problems, including global warming, which exacerbates natural disasters and human health. Cu-based catalysts have shown great activity in the reduction of CO, but the mechanism of CO activation remains ambiguous. In this work, we performed density functional theory (DFT) calculations to investigate the hydrogenation of CO on Cu(211)-Rh, Cu(211)-Ni, Cu(211)-Co, and Cu(211)-Ru surfaces.

Cellulose Regeneration in Imidazolium-Based Ionic Liquids and Antisolvent Mixtures: A Density Functional Theory Study.

Cellulose can be dissolved in ionic liquids (ILs), and it can be recovered by adding antisolvent such as water or alcohol. In addition, the regenerated cellulose can be used for textiles, degradable membranes, hydrogels/aerogels, . However, the regenerated mechanism of cellulose remains ambiguous.

Fischer-Helferich glycosidation mechanism of glucose to methyl glycosides over Al-based catalysts in alcoholic media.

The Fischer-Helferich glycosidation reaction is generally the initial step in the conversion of glucose to levulinate in alcohol media. However, the relevant molecular mechanism catalyzed by Al-based catalysts is still not well understood. In this work, the reaction mechanism of the glycosidation from glucose to methyl glycosides catalyzed by Al coordinated with methanol/methoxyl was investigated through density functional theory (DFT) calculations.

Probing the mechanism of the conversion of methyl levulinate into γ-valerolactone catalyzed by Al(OiPr) in an alcohol solvent: a DFT study.

Biomass-derived γ-valerolactone (GVL) is a versatile chemical that can be used in various fields. As an efficient, cheap, and sustainable catalyst, Al(OiPr) has been successfully used in the conversion of methyl levulinate (ML) to GVL in the solvent isopropanol (IPA). However, the molecular mechanism of this conversion catalyzed by Al(OiPr) remains ambiguous.

Selective Aerobic Oxidation of C-H Bonds Catalyzed by Yeast-Derived Nitrogen, Phosphorus, and Oxygen Codoped Carbon Materials.

Nitrogen, phosphorus, and oxygen codoped carbon catalysts were successfully synthesized using dried yeast powder as a pyrolysis precursor. The yeast-derived heteroatom-doped carbon (yeast@C) catalysts exhibited outstanding performance in the oxidation of C-H bonds to ketones and esters, giving excellent product yields (of up to 98% yield) without organic solvents at low O pressure (0.1 MPa).

Theoretical Mechanism on the Cellulose Regeneration from a Cellulose/EmimOAc Mixture in Anti-Solvents.

The experiments on cellulose dissolution/regeneration have made some achievements to some extent, but the mechanism of cellulose regeneration in ionic liquids (ILs) and anti-solvent mixtures remains elusive. In this work, the cellulose regeneration mechanism in different anti-solvents, and at different temperatures and concentrations, has been studied with molecular dynamics (MD) simulations. The IL considered is 1-ethyl-3-methylimidazolium acetate (EmimOAc).

Mechanistic insight into the roles of anions and cations in the degradation of poly(ethylene terephthalate) catalyzed by ionic liquids.

Ionic liquids (ILs) have shown high catalytic activity in the degradation of poly(ethylene terephthalate) (PET), but the effects of the anions and cations, as well as the mechanism, remain ambiguous. Glycolysis is an important recycling method that converts waste PET into monomers through various chemical reactions. To reveal the role of ILs and the molecular mechanism of the glycolysis of PET, density functional theory (DFT) calculations have been carried out for the possible pathways for the generation of bis(hydroxyethyl)terephthalate (BHET) catalyzed by isolated anions/cations and ion pairs at different sites.

Theoretical study on the microscopic mechanism of lignin solubilization in Keggin-type polyoxometalate ionic liquids.

Keggin-type polyoxometalate derived ionic liquids (POM-ILs) have recently been presented as effective solvent systems for biomass delignification. To investigate the mechanism of lignin dissolution in POM-ILs, the system involving POM-IL ([C4C1Im][PWO]) and guaiacyl glycerol-β-guaiacyl ether (GGE), which contains a β-O-4 bond (the most dominant bond moiety in lignin), was studied using quantum mechanical calculations and molecular dynamics simulations. These studies show that more stable POM-IL structures are formed when [C4C1Im] is anchored in the connecting four terminal oxygen region of the [PWO] surface.

Theoretical studies on the noncovalent interaction of fructose and functionalized ionic liquids.

As a new kind of solvent and catalyst, the functionalized ionic liquids (ILs) had been successfully used in the conversion of fructose to high value-added biofuels. In this work, a detailed density functional theory (DFT) calculation had been carried out to investigate the interactions of fructose-ILs system. To study the effect of different anions and cations on the interaction with fructose, 25 different kinds of functionalized imidazolium-based ILs were calculated by using M06-2X-D3/6-311 + G** level.

Theoretical studies on glycolysis of poly(ethylene terephthalate) in ionic liquids.

Ionic liquids (ILs) present superior catalytic performance in the glycolysis of ethylene terephthalate (PET). To investigate the microscopic degradation mechanism of PET, density functional theory (DFT) calculations have been carried out for the interaction between ILs and dimer, which is considered to symbolize PET. We found that hydrogen bonds (H-bonds) play a critical role in the glycolysis process.

P-N Conversion in a Water-Ionic Liquid Binary System for Nonredox Thermocapacitive Converters.

An intriguing p-n conversion of thermoelectric property was observed in a water-ionic liquid ([EMIm][Ac]) binary system with precise control over water content. The highest p-type and n-type Seebeck coefficient were optimized at water-[EMIm][Ac] molar ratio of 2:1 and 4:1, respectively. DFT calculation illustrates that a configuration of solvent separation ion pairs is preferred at the water-[EMIm][Ac] molar ratio of 4:1, leading to the p-n conversion through weakening interaction between anion clusters and gold electrodes.