Measuring 1HN temperature coefficients in invisible protein states by relaxation dispersion NMR spectroscopy

Guillaume Bouvignies, Pramodh Vallurupalli, Matthew H.J. Cordes, D. Flemming Hansen, Lewis E. Kay

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

A method based on the Carr-Purcell-Meiboom- Gill relaxation dispersion experiment is presented for measuring the temperature coefficients of amide proton chemical shifts of low populated 'invisible' protein states that exchange with a 'visible' ground state on the millisecond time-scale. The utility of the approach is demonstrated with an application to an I58D mutant of the Pfl6 Cro protein that undergoes exchange between the native, folded state and a cold denatured, unfolded conformational ensemble that is populated at a level of 6% at 2.5°C. A wide distribution of amide temperature coefficients is measured for the unfolded state. The distribution is centered about -5.6 ppb/K, consistent with an absence of intra-molecular hydrogen bonds, on average. However, the large range of values (standard deviation of 2.1 ppb/K) strongly supports the notion that the unfolded state of the protein is not a true random coil polypeptide chain.

Original languageEnglish (US)
Pages (from-to)13-18
Number of pages6
JournalJournal of Biomolecular NMR
Volume50
Issue number1
DOIs
StatePublished - May 1 2011

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Keywords

  • Amide protons
  • CPMG relaxation dispersion
  • Cold denaturation
  • Temperature coefficients

ASJC Scopus subject areas

  • Biochemistry
  • Spectroscopy

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