A spirocyclohexyl nitroxide amino acid spin label for pulsed EPR spectroscopy distance measurements

Andrzej Rajca, Velavan Kathirvelu, Sandip K. Roy, Maren Pink, Suchada Rajca, Santanu Sarkar, Sandra S. Eaton, Gareth R. Eaton

Research output: Contribution to journalArticle

41 Scopus citations


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 a-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.

Original languageEnglish (US)
Pages (from-to)5778-5782
Number of pages5
JournalChemistry - A European Journal
Issue number19
StatePublished - May 17 2010



  • EPR spectroscopy
  • Radicals
  • Spin labels spin relaxation
  • Spiro compounds

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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