Abstract: A method for synthesis of new covalently linked spin-labeled cyclodextrin (CD) via the attachment of nitronyl nitroxide 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl to permethylated beta-cyclodextrin is described. Electron spin echo envelope modulation (ESEEM) studies demonstrate that the new spin-labeled CD exhibits dynamic equilibrium between conformations with radical fragment capping the cavity of CD and radical fragment located outside the cavity. In solution, nitronyl nitroxide attached to CD retains its sensitivity to nitric oxide (NO), as reaction with NO leads to formation of iminonitroxide fragment evidenced by continuous-wave (CW) electron paramagnetic resonance (EPR). At the same time, CW EPR study of the reaction with ascorbic acid shows that the described binding of nitronyl nitroxide to CD does not provide higher stability of radical towards the reduction, and the corresponding rate constants are close to those obtained for free nitronyl nitroxide. Plausible explanations of these observations are discussed.

Cite: Strizhakov R.K. , Tretyakov E.V. , Medvedeva A.S. , Novokshonov V.V. , Vasiliev V.G. , Ovcharenko V.I. , Krumkacheva O.A. , Fedin M.V. , Bagryanskaya E.G.
Permethyl-beta-Cyclodextrin Spin-Labeled with Nitronyl Nitroxide: Synthesis and EPR Study
Applied Magnetic Resonance. 2014. V.45. N10. P.1087-1098. DOI: 10.1007/s00723-014-0591-x WOS Scopus РИНЦ

Dates:

Published online:	Sep 13, 2014
Published print:	Oct 1, 2014

Identifiers:

Web of science	WOS:000344058800011
Scopus	2-s2.0-84919452706
Elibrary	24020642
OpenAlex	W2113133496

Altmetrics: