Wydział Chemii

Mariusz Jaremko

Łukasz Jaremko

Adam Mazur

Maciej Makowski

Marek Lisowski

2013

Amino Acids

45

865-875

10.1007/s00726-013-1534-9

Naukowa

Angielski

Artykuł

Conformations of three pairs of dehydropeptides with the opposite configuration of the ΔPhe residue, Boc-Gly-Δ(Z/E)Phe-Phe-p-NA (Z- p -NA and E- p -NA), Boc-Gly-Δ(Z/E)Phe-Phe-OMe (Z-OMe and E-OMe), and Boc-Gly-Δ(Z/E)Phe-Phe-OH (Z-OH and E-OH) were compared on the basis of CD and NMR studies in MeOH, TFE, and DMSO. The CD results were used as the additional input data for the NMR-based calculations of the detailed solution conformations of the peptides. It was found that Z- p -NA, E- p -NA, Z-OMe, and Z-OH adopt the β-turn conformations and E-OMe and E-OH are unordered. There are two overlapping type III β-turns in Z- p -NA, type II' β-turn in E- p -NA, and type II β-turn in Z-OMe and Z-OH. The results obtained indicate that in the case of methyl esters and peptides with a free carboxyl group, Δ(Z)Phe is a much stronger inducer of ordered conformations than Δ(E)Phe. It was also found that temperature coefficients of the amide protons are not reliable indicators of intramolecular hydrogen bonds donors in small peptides.

Dehydropeptides, Dehydrophenylalanine configuration , Circular dichroism, Nuclear magnetic resonance, Dehydropeptide conformation, emperature coefficients of amide protons

http://dx.doi.org/10.1007/s00726-013-1534-9

http://link.springer.com