Molecular planarity of penta-p-phenylene (P5P) and several substituted derivatives with four side chains of various lengths, including deca(ethylene glycol) groups, is discussed by considering the changes in the intensity ratio between the Raman bands recorded at 1280 and 1220 cm(-1). The intensity ratio between both bands I(1280)/I(1220) shows a small increase with the size of the substituent, indicating a high rigidity for all these compounds, even those with long oligo(ethylene glycol) side chains. This result is important given that these phenylene derivatives are versatile building blocks for the construction of nanometric tripod-shaped adsorbates for biological applications since the side chains should prevent the nonspecific interaction with proteins.
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http://dx.doi.org/10.1021/jp8012893 | DOI Listing |
Mol Phys
March 2024
Department of Physics, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States.
The stability of proteins and small peptides depends on the way they interact with the surrounding water molecules. For small peptides, such as -helical polyalanine (polyALA), water molecules can weaken the intramolecular hydrogen-bonds (HB) formed between the peptide backbone O and NH groups which are responsible for the -helix structure. Here, we perform molecular dynamics simulations to study the hydration of polyALA, polyserine (polySER), and other homopolymer peptide -helices at different temperatures and pressures.
View Article and Find Full Text PDFChemistry
January 2025
Middle East Technical University: Orta Dogu Teknik Universitesi, Chemistry, Universiteler Mah., 06800, Cankaya, TURKEY.
This study introduces a new donor group capable of activating click-type [2+2] cycloaddition-retroelectrocyclizations, generally known for their limited scope. Target chromophores were synthesized using isocyanate-free urethane synthesis. The developed synthetic method allows for the tuning of the optical properties of the chromophores by modifying the donor groups, the acceptor units, and the side chains.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies, Taizhou University, 1139 Shifu Avenue, Taizhou 318000, Zhejiang,China.
We report an enhanced recognition and redox-responsive reversible host-guest system based on ester-bearing calix[]phenoxazines. The carbonyl groups, oriented toward the cavity, act as the extra binding sites to enhance the binding affinity, which is confirmed by NMR and FTIR experiments and single-crystal structure analysis. Due to the oxidizable nature of calix[]phenoxazine, a redox-controlled reversible response is established.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.
Streptococcus mutans, the causative agent of human dental caries, expresses a cell wall attached Serotype c-specific Carbohydrate (SCC) that is critical for cell viability. SCC consists of a polyrhamnose backbone of →3)α-Rha(1 → 2)α-Rha(1→ repeats with glucose (Glc) side-chains and glycerol phosphate (GroP) decorations. This study reveals that SCC has one predominant and two more minor Glc modifications.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Biophysics and Medical Technology, Department of Physics, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
Schizophyllan (SPG) is a semi-flexible, triple-helical polysaccharide with attractive properties as an efficient viscosifying compound and biological response modifier. We report microrheological characterization of schizophyllan as dispersed in solution and the changes associated when crosslinked with chitosan over an extended frequency range using diffusing wave spectroscopy (DWS). A SPG with high molecular weight (M = 1.
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