Synthesis and Properties of (1 R ( S ),5 R ( S ),7 R ( S ),8 R ( S ))-1,8-Bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl: Reduction-Resistant Spin Labels with High Spin Relaxation Times

• Published in: International journal of molecular sciences Vol. 24; no. 14
• Main Authors: Khoroshunova, Yulia V, Morozov, Denis A, Kuznetsov, Danil A, Rybalova, Tatyana V, Glazachev, Yurii I, Bagryanskaya, Elena G, Kirilyuk, Igor A
• Format: Journal Article
• Language: English
• Published: Switzerland 15.07.2023
• Subjects: Electron Spin Resonance Spectroscopy - methods; Nitrogen Oxides - chemistry; Spin Labels; sterically shielded nitroxides; pyrrolidine nitroxides; spin labels; nitrones; 6-azadispiro[4.1.4.2]tridecane; dispiro[pyrrolidine-2,1′-cyclopentane-5,1″-cyclopentane]; 1,3-dipolar cycloaddition
• ISSN: 1422-0067

Site-directed spin labeling followed by investigation using Electron Paramagnetic Resonance spectroscopy is a rapidly expanding powerful biophysical technique to study structure, local dynamics and functions of biomolecules using pulsed EPR techniques and nitroxides are the most widely used spin labels. Modern trends of this method include measurements directly inside a living cell, as well as measurements without deep freezing (below 70 K), which provide information that is more consistent with the behavior of the molecules under study in natural conditions. Such studies require nitroxides, which are resistant to the action of biogenic reductants and have high spin relaxation (dephasing) times, T . (1 ( ),5 ( ),7 ( ),8 ( ))-1,8-bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl is a unique nitroxide that combines these features. We have developed a convenient method for the synthesis of this radical and studied the ways of its functionalization. Promising spin labels have been obtained, the parameters of their spin relaxation T and T have been measured, and the kinetics of reduction with ascorbate have been studied.