Solid State NMR Study
of Thermal Processes in Nanoassemblies
Formed by Dipeptides
Magdalena Jaworska
Agata Jeziorna
Ewelina Drabik
Marek J. Potrzebowski
10.1021/jp302616n.s001
https://acs.figshare.com/articles/journal_contribution/Solid_State_NMR_Study_of_Thermal_Processes_in_Nanoassemblies_Formed_by_Dipeptides/2515741
Three linear dipeptides Phe-Phe (FF), Tyr-Ala (YA) and
Asp-Phe(OMe)
(DF-OMe, also known as aspartame) were investigated via solid state
(SS) NMR spectroscopy, differential scanning calorimetry (DSC), mass
spectrometry, and scanning electron microscopy (SEM). Both 1D and
2D SS NMR techniques (<sup>1</sup>H MAS, <sup>13</sup>C CP/MAS, and <sup>1</sup>H–<sup>13</sup>C inverse HETCOR ultrafast MAS) were
used to study the thermal stability and chemical processes of the
self-assembled structures: peptide nanotubes (PNTs) and peptide nanowires
(PNWs). Each of the investigated dipeptides underwent thermal rearrangement
to cyclic dipeptides, also known as diketopiperazines (DKP). Employment
of variable temperature (VT) <sup>13</sup>C NMR measurements revealed
that the cyclization of Phe-Phe (FF) PNT began at a temperature of
373 K, which is lower than the temperature reported previously. The
process to form FF DKP would be anticipated to occur because of the
removal of water from the hydrophilic channel of the PNTs. When FF
PNT is thermally treated carefully and the subtle nanostructure is
not damaged, the empty channel can be refilled with water during the
diffusion process. An analysis of the thermal stability of YA dipeptide
revealed that, as in case of FF, a synthesis of YA DKP is a facile
process and can be performed in NMR rotor. YA DKP forms PNTs, which
are more thermally stable than FF PNTs. Finally, aspartame forms fibrils
and peptide nanowires, which is particulary important because it is
commonly applied in the food industry.
2012-06-07 00:00:00
HETCOR ultrafast MAS
DSC
YA DKP forms PNTs
Solid State NMR Study
aspartame forms fibrils
13 C NMR measurements
dipeptide
form FF DKP
SEM
peptide nanowires
scanning electron microscopy
CP
SS
VT
PNW