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A Spirocyclohexyl Nitroxide Amino Acid Spin Label for Pulsed EPR Spectroscopy Distance Measurements
Author(s) -
Rajca Andrzej,
Kathirvelu Velavan,
Roy Sandip K.,
Pink Maren,
Rajca Suchada,
Sarkar Santanu,
Eaton Sandra S.,
Eaton Gareth R.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200903102
Subject(s) - electron paramagnetic resonance , nitroxide mediated radical polymerization , spectroscopy , site directed spin labeling , chemistry , spin label , liquid nitrogen , dephasing , pulsed epr , liquid helium , macromolecule , analytical chemistry (journal) , crystallography , nuclear magnetic resonance , materials science , spin echo , polymer , organic chemistry , copolymer , condensed matter physics , helium , physics , biochemistry , quantum mechanics , radiology , magnetic resonance imaging , medicine , radical polymerization
Site‐directed spin labeling and EPR spectroscopy offer accurate, sensitive tools for the characterization of structure and function of macromolecules and their assemblies. A new rigid spin label, spirocyclohexyl nitroxide α‐amino acid and its N ‐(9‐fluorenylmethoxycarbonyl) derivative, have been synthesized, which exhibit slow enough spin‐echo dephasing to permit accurate distance measurements by pulsed EPR spectroscopy at temperatures up to 125 K in 1:1 water/glycerol and at higher temperatures in matrices with higher glass transition temperatures. Distance measurements in the liquid nitrogen temperature range are less expensive than those that require liquid helium, which will greatly facilitate applications of pulsed EPR spectroscopy to the study of structure and conformation of peptides and proteins.