The biological activities of N-substituted glycine oligomers (peptoids) have been the subject of extensive research. As compared to peptides, both the cis and trans conformations of the backbone amide bonds of peptoids can be significantly populated. Thus, peptoids are mixtures of configurational isomers, with the number of isomers increasing by a factor of 2 with each additional monomer residue. Here we report the results of a study of the kinetics and equilibria of cis/trans isomerization of the amide bonds of N-acetylated peptoid monomers, dipeptoids, and tripeptoids by NMR spectroscopy. Resonance intensities indicate the cis conformation of the backbone amide bonds of the peptoids studied is more populated than is generally the case for the analogous secondary amide bond to proline residues in acyclic peptides. Rate constants were measured by inversion-magnetization transfer techniques over a range of temperatures, and activation parameters were derived from the temperature dependence of the rate constants. The rate of cis/trans isomerization by rotation around the amide bonds in the peptoids studied is generally slower than that around amide bonds to proline residues and takes place on the NMR inversion-magnetization transfer time scale only by rotation around the amide bond to the C-terminal peptoid residue.
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http://dx.doi.org/10.1021/ja0740925 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
School of Food Science and Technology, Jiangnan University, Wuxi, PR China.
This study investigates camel milk protein structural dynamics during digestion using Fourier Transform Infrared (FTIR) spectroscopy and Two-Dimensional Infrared (2D-IR) homo-correlation and hetero-correlation analysis. The synchronous 2DIR homo-correlation map reveals that NH bending and C-N stretching vibrations (amide II) are sensitive to digestion, indicating significant impacts on secondary structures. The asynchronous 2DIR homo-correlation indicates a stepwise process, where initial disruptions in NH interactions precede changes in CO stretching vibrations (amide I), highlighting the sequence of structural alterations during protein unfolding and degradation.
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January 2025
Laboratory of Advanced Theranostic Materials and Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
Amorphous solid dispersion (ASD) is one of the most studied strategies for improving the dissolution performance of poorly water-soluble drugs, but ASDs often have low drug loadings, thereby necessitating larger dosage sizes. This study intended to create Soluplus® (SOL)-based microparticle ASDs with high drug loading (up to 60 w/w%) and long-term stability (at least 16 months) using electrospraying to enhance the dissolution of poorly water-soluble celecoxib (CEL). X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses showed that the electrosprayed SOL-CEL microparticles were amorphous, and Fourier transform infrared spectroscopy (FTIR) data indicated the presence of hydrogen bonding between SOL and CEL in the microparticles, which helped stabilize the ASDs.
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January 2025
Institute of Chemistry, Vietnam Academy of Science and Technology Hanoi Vietnam
In this paper, a series of novel quinazoline-4(3)-one-2-carbothioamide derivatives (8a-p) were designed and synthesized the Wilgerodt-Kindler reaction between 2-methylquinazoline-4-one 10 and amines using S/DMSO as the oxidizing system. Their characteristics were confirmed by IR, NMR, HRMS spectra, and their melting point. These novel derivatives (8a-p) were evaluated for their anti-inflammatory activity by inhibiting NO production in lipopolysaccharide (LPS)-activated RAW 264.
View Article and Find Full Text PDFBioelectrochemistry
January 2025
School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China. Electronic address:
A ratiometric electrochemical aptasensor was developed for ultra-sensitive detection of cortisol using aptamer (Apt) as recognition element, methylene blue (MB) as signal probe, and zirconium metal-organic framework (Zr-MOF) as carrier loaded with abundant MB for signal amplification. The carboxylated multi-walled carbon nanotubes (cMWCNTs)-modified Au electrode showed excellent electrochemical performance to immobilize complementary DNA (cDNA) for hybridizing with MB@Zr-MOF-Apt via amide bonds. In the presence of cortisol, it would compete with cDNA for binding the Apt, resulting in the detachment of MB@Zr-MOF-Apt complex from the electrode surface, and the electrochemical signal of MB was decreased, while that of [Fe(CN)] was basically unchanged.
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January 2025
Infectious Diseases Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu, Jammu and Kashmir 180001, India.
The insertion of β-amino acids and replacement of the amide bond with a urea bond in antimicrobial peptide sequences are promising approaches to enhance the antibacterial activity and improve proteolytic stability. Herein, we describe the synthesis, characterization, and antibacterial activity of short αβ cationic hybrid peptides LA-Orn-βAcc-PEA, ; LA-Lys-βAcc-PEA, ; and LA-Arg-βAcc-PEA, in which a C12 lipid chain is conjugated at the N terminus of peptide through urea bonds. Further, we evaluated all the peptides against both and methicillin-resistant (MRSA) and their multidrug resistant (MDR) clinical isolates.
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