Overhauser dynamic nuclear polarization and molecular dynamics simulations using pyrroline and piperidine ring nitroxide radicals

Brandon D. Armstrong, Patricia Soto, Joan Emma Shea, Songi Han

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

The efficiency of Overhauser dynamic nuclear polarization (DNP) depends on the local dynamics modulating the dipolar coupling between the two interacting spins. By attaching nitroxide based spin labels to molecules and by measuring the 1H DNP response of solvent water, information about the local hydration dynamics near the spin label can be obtained. However, there are two commonly used types of nitroxide ring structures; a pyrroline based and a piperidine based molecule. It is important to know when comparing different experiments, whether changes in DNP enhancements are due to changes in local hydration dynamics or because of the different spin label structures. In this study we investigate the key parameters affecting DNP signal enhancements for 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-oxyl, a 5-membered ring nitroxide radical, and for 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy, a 6-membered ring nitroxide radical. Using X-Band DNP, field cycling relaxometry, and molecular dynamics simulations, we conclude that the key parameters affecting the DNP amplitude of the 1H signal of water to be equal when using either nitroxide. Thus, experiments measuring hydration dynamics using either type of spin labels may be compared.

Original languageEnglish (US)
Pages (from-to)137-141
Number of pages5
JournalJournal of Magnetic Resonance
Volume200
Issue number1
DOIs
StatePublished - Sep 1 2009

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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