The transition from alpha-helix to random coil of the titrating polyamino acid co-poly-L-(lysine, phenylalanine), (p-(Lys,Phe)), has been investigated as a function of pH and ionic strength in aqueous solution and at the air-water interface by means of circular dichroism (CD) spectroscopy and the Langmuir surface film balance technique. The results strongly suggest that the helix-coil transition for peptides at the air-water interface can be determined by using the two-dimensional Flory exponent, nu, to express the pH dependent peptide surface conformation. The helix-coil titration curve of p-(Lys,Phe) shifts approximately 2.5 pH units towards lower pH at the air-water interface, as compared with the bulk solution. This finding is of relevance for the understanding of conformation and conformational changes of membrane-transporting and membrane penetrating peptides as well as for the use of peptides in molecular devices.
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http://dx.doi.org/10.1016/j.bpc.2005.01.007 | DOI Listing |
Sci Rep
January 2025
School of Engineering, Westlake University, Hangzhou, Zhejiang, China.
The film water, with an exceptional capacity to maintain a premelting, liquid-like state even under subzero conditions, provides a potential dynamic conduit for the movement of water in frozen soils. However, the distinctive structural and dynamic characteristics of film water have not been comprehensively elucidated. In this study, molecular dynamics (MD) simulations were conducted to examine the freezing of a system containing ice, water, silica, and gas.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China.
Hydroxyl radical (·OH) plays a crucial role in atmospheric chemistry, regulating the oxidative potential and aerosol composition. This study reveals an unprecedented source of ·OH in the atmosphere: mineral dust-bearing microdroplet aerosols. We demonstrate that Kaolin clay particles in microdroplet aerosols trigger rapid ·OH production upon solar irradiation, with rates reaching an order of at least 10 M s.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
DWI at RWTH Aachen, Macromolecular Chemistry, Pauwelsstrasse 8, 52056, Aachen, GERMANY.
The development of sustainable synthesis route to produce functional and bioactive polymer colloids has attracted much attention. Most strategies are based on the polymerization of monomers or crosslinking of prepolymers by enzyme- or cell-mediated reactions or specific catalysts in confined emulsions. Herein, a facile solution spray method was developed for spontaneous synthesis of microgels without use of confined emulsion, additional initiators/catalysts and deoxygenation, which addresses the challenges in traditional microgel synthesis.
View Article and Find Full Text PDFACS ES T Water
January 2025
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States.
Alkylated polycyclic aromatic hydrocarbons (PAHs) are abundant constituents of many PAH mixtures and contribute to risk at contaminated sites. Despite their abundance, the movement of alkylated PAHs remains understudied relative to unsubstituted PAHs. In the present study, passive sampling devices were deployed in the air, water, and sediments at 11 locations across multiple seasons to capture spatial and temporal variability in the abundance and movement of alkylated PAHs at a Brownsfield creosote site in Oregon, USA.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, University of Michigan, 930 North University Avenue Ann Arbor, Michigan 48103, United States.
Poly(dimethylsiloxane) (PDMS) materials have been widely researched and applied as fouling-release coatings. Incorporation of silicone oils into PDMS has been shown to improve the antifouling properties of PDMS materials. In this research, we applied sum frequency generation (SFG) vibrational spectroscopy to study PDMS materials incorporated with various silicone oils containing phenyl groups in air, water, and protein solutions.
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