A NITROXIDE-MALEIMIDE SPIN LABEL

A nitroxide-maleimide spin label.

was chemically bonded to poly-L-lysine and to bovine serum albumin (BSA) and showed a paramagnetic resonance spectrum that was sensitive to known structural changes in these molecules, such as those produced by changes in pH.2 This nitroxide-isocyanate is unfortunately not an ideal spin-labeling reagent since it is unstable and thus difficult to purify, and moreover the isocyanate group is rapi...

A semi-rigid isoindoline-derived nitroxide spin label for RNA.

A new isoindoline-derived benzimidazole nitroxide spin label, ImUm, was synthesized and incorporated into RNA oligoribonucleotides. ImUm is the first example of a conformationally unambiguous spin label for RNA, in which the nitroxide N-O bond lies on the same axis as the single bond used to attach the rigid isoindoline-based spin label to a uridine base. This results in minimal displacement of...

In Vivo Nitroxide Spin Label Imaging by Overhauser Effect

Double resonance is a well known development of magnetic resonance in which one resonant transition of a system is excited while simultaneously a different transition is monitored. Since the first works of the early fifties, double resonance has been widely applied in NMR and in EPR [1]. Only recently, double resonance has been used for imaging [2] and for in vivo applications [3]. The possibil...

A nucleoside that contains a rigid nitroxide spin label: a fluorophore in disguise.

The spatial effect of protein deuteration on nitroxide spin-label relaxation: Implications for EPR distance measurement

Pulsed electron-electron double resonance (PELDOR) coupled with site-directed spin labeling is a powerful technique for the elucidation of protein or nucleic acid, macromolecular structure and interactions. The intrinsic high sensitivity of electron paramagnetic resonance enables measurement on small quantities of bio-macromolecules, however short relaxation times impose a limit on the sensitiv...