N-[1-(4-(4-fluorophenyl)-2,6-dioxocyclohexylidene)ethyl] (Fde) protected amino acids have been prepared and applied in solid-phase peptide synthesis monitored by gel-phase (19)F NMR spectroscopy. The Fde protective group could be cleaved with 2% hydrazine or 5% hydroxylamine solution in DMF as determined with gel-phase (19)F NMR spectroscopy. The dipeptide Ac-L-Val-L-Val-NH(2) 12 was constructed using Fde-L-Val-OH and no noticeable racemization took place during the amino acid coupling with N,N'-diisopropylcarbodiimide and 1-hydroxy-7-azabenzotriazole or Fde deblocking. To extend the scope of Fde protection, the hydrophobic nonapeptide LLLLTVLTV from the signal sequence of mucin MUC1 was successfully prepared using Fde-L-Leu-OH at diagnostic positions.
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http://dx.doi.org/10.1002/psc.1110 | DOI Listing |
Biophys J
November 2024
Departement of Chemistry, Université du Québec à Montréal, Montreal, Québec, Canada. Electronic address:
Fluorine-19 is an ideal nucleus for studying biological systems using NMR due to its rarity in biological environments and its favorable magnetic properties. In this work, we used a mixture of monofluorinated palmitic acids (PAs) as tracers to investigate the molecular interaction of the fluorinated drug rosuvastatin in model lipid membranes. More specifically, PAs labeled at the fourth and eighth carbon positions of their acyl chains were coincorporated in phospholipid bilayers to probe different depths of the hydrophobic core.
View Article and Find Full Text PDFChemSusChem
February 2016
Green Chemistry Centre of Excellence, University of York, Department of Chemistry, Heslington, York, YO10 5DD, UK.
The processes involved in the transformation of non-porous, native polysaccharides to their highly porous equivalents introduce significant molecular complexity and are not yet fully understood. In this paper, we propose that distinct changes in polysaccharide local short-range ordering promotes and directs the formation of meso- and micro-pores, which are investigated here using N2 sorption, FTIR, and solid-state (13)C NMR. It is found that an increase in the overall double helical amylose content, and their local association structures, are responsible for formation of the porous polysaccharide gel phase.
View Article and Find Full Text PDFBiochim Biophys Acta
March 2015
Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021 Karlsruhe, Germany; Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany. Electronic address:
To understand the molecular mechanisms of amphiphilic membrane-active peptides, one needs to study their interactions with lipid bilayers under ambient conditions. However, it is difficult to control the pH of the sample in biophysical experiments that make use of mechanically aligned multilamellar membrane stacks on solid supports. HPLC-purified peptides tend to be acidic and can change the pH in the sample significantly.
View Article and Find Full Text PDFBiochim Biophys Acta
September 2014
Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021 Karlsruhe, Germany; Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany. Electronic address:
Many amphiphilic antimicrobial peptides permeabilize bacterial membranes via successive steps of binding, re-alignment and/or oligomerization. Here, we have systematically compared the lipid interactions of two structurally unrelated peptides: the cyclic β-pleated gramicidin S (GS), and the α-helical PGLa. (19)F NMR was used to screen their molecular alignment in various model membranes over a wide range of temperatures.
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2009
Karlsruhe Institute of Technology, Institute of Biological Interfaces (IBG-2), Forschungszentrum Karlsruhe, Karlsruhe, Germany.
A semi-empirical method for the prediction of chemical shifts, based on bond polarization theory, has recently been introduced for (13)C. Here, we extended this approach to calculate the (19)F chemical shift tensors of fluorine bound to aromatic rings and in aliphatic CF(3) groups. For the necessary parametrization, ab initio chemical shift calculations were performed at the MP2 level for a set of fluorinated molecules including tryptophan.
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