Cyclic peptides represent a large class of substances that occur in nature with important biological and medical functions. Synthetic cyclic peptides are used as artificial receptors due to a series of advantages over conventional receptors. In order to optimize their binding abilities, investigations of their intrinsic structural properties especially with regard to the influence of different amino acid residues are fundamental. Here we report the structural analysis of two synthetic cyclic tetrapeptides cyclo[l-Tyr(Me)-d-Pro-l-Ala-d-Pro] (CPAla) and cyclo[l-Tyr(Me)-d-Pro-l-Glu(Me)-d-Pro] (CPGlu) in a molecular beam by means of combined IR/UV spectroscopic techniques. Structural assignments were achieved by comparing experimentally obtained vibrations and harmonically calculated frequencies including dispersion corrections (B3LYP-D3/TZVP). The investigated cyclic peptides contain an arrangement of an amino acid sequence which is no longer symmetric compared to the former investigations of the cyclo[l-Tyr(Me)-d-Pro] peptide. It turns out that all investigated compounds prefer conformations stabilized by two internal hydrogen bonds. In the case of CPGlu containing a flexible side chain with a terminal hydrogen bond acceptor an additional structure was observed in which a hydrogen bond between the terminal carboxylate group and a ring NH group is formed.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c6cp08696a | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Clinicopathological and in Silico Insights into Male Infertility: Agerelated Trends and Anti-sperm Antibodies Post COVID-19 Vaccination.
Curr Med Chem
January 2025
Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
Background: Infertility was often considered a female issue, but male infertility emerged significantly after the Covid-19 pandemic. Hence, assessments are crucial for planning policies on health care and family planning and reasons thereof post vaccinations.
Material And Methods: The present study was a case-control, dual-centers, prospective study with normal sperm parameters.
Unit-cell parameters determination from a set of independent electron diffraction zonal patterns.
Acta Crystallogr A Found Adv
March 2025
Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-11 Mustuno, Atsuta-ku, Nagoya, 456-8587, Japan.
Due to the short de Broglie wavelength of electrons compared with X-rays, the curvature of their Ewald sphere is low, and individual electron diffraction patterns are nearly flat in reciprocal space. As a result, a reliable unit-cell determination from a set of randomly oriented electron diffraction patterns, an essential step in serial electron diffraction, becomes a non-trivial task. Here we describe an algorithm for unit-cell determination from a set of independent electron diffraction patterns, as implemented in the program PIEP (Program for Interpreting Electron diffraction Patterns), written in the early 1990s.
View Article and Find Full Text PDFsynergistically supports systemic plant defense response in against .
Front Plant Sci
January 2025
Plant Biochemistry and Physiology, Bielefeld University, Bielefeld, Germany.
The network of antagonistic, neutral, and synergistic interactions between (micro)organisms has moved into the focus of current research, since in agriculture, this knowledge can help to develop efficient biocontrol strategies. Applying the nematophagous fungus as biocontrol agent to manage the root-knot nematode is a highly promising strategy. To gain new insight into the systemic response of plants to a plant-parasitic nematode and a nematophagous fungus, was inoculated with and/or and subjected to transcriptome and metabolome analysis of leaves.
View Article and Find Full Text PDFExpedient discovery of fluorogenic amino acid-based probes one-pot palladium-catalysed arylation of tyrosine.
Chem Sci
January 2025
School of Chemistry, University of Glasgow Joseph Black Building, University Avenue Glasgow G12 8QQ UK
To overcome the limitations of using large extrinsic chromophores for biological imaging, fluorescent unnatural α-amino acids have been widely adopted as intrinsic peptidic probes. Although various classes have been successfully utilised for imaging applications, novel amino acid probes readily prepared through operationally simple synthetic methodology are still required. Here, we report a new approach for the synthesis of unnatural α-amino acids a one-pot process involving activation and palladium-catalysed arylation of tyrosine.
View Article and Find Full Text PDFPvHCt, a 23-amino acid long, histidine-rich peptide derived from shrimp, becomes strongly antimicrobial upon Cu(ii) ion binding. We describe Zn(ii) and Cu(ii) complexes of this peptide, aiming to understand how metal binding and structure correlates to biological activity. Using NMR, UV-vis, CD and FTIR spectroscopies, along with cyclic voltammetry, potentiometry, and DFT calculations, we demonstrate that Cu(ii) binds to the central and C-terminal regions of the peptide, inducing significant structural changes.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!