Detection of Ras GTPase protein radicals through immuno-spin trapping

Michael F. Davis, Li Zhou, Marilyn Ehrenshaft, Kalina Ranguelova, Harsha P. Gunawardena, Xian Chen, Marcelo G. Bonini, Ronald P. Mason, Sharon L. Campbell*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Over the past decade immuno-spin trapping (IST) has been used to detect and identify protein radical sites in numerous heme and metalloproteins. To date, however, the technique has had little application toward nonmetalloproteins. In this study, we demonstrate the successful application of IST in a system free of transition metals and present the first conclusive evidence of NO-mediated protein radical formation in the HRas GTPase. HRas is a nonmetalloprotein that plays a critical role in regulating cell-growth control. Protein radical formation in Ras GTPases has long been suspected of initiating premature release of bound guanine nucleotide. This action results in altered Ras activity both in vitro and in vivo. As described herein, successful application of IST may provide a means for detecting and identifying radical-mediated Ras activation in many different cancers and disease states in which Ras GTPases play an important role.

Original languageEnglish (US)
Pages (from-to)1339-1345
Number of pages7
JournalFree Radical Biology and Medicine
Issue number6
StatePublished - Sep 15 2012
Externally publishedYes


  • Free radicals
  • Immuno-spin trapping
  • Protein radical
  • Radical-mediated activation
  • Ras GTPase

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

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