Measuring (1)H (N) temperature coefficients in invisible protein states by relaxation dispersion NMR spectroscopy.
 

Measuring (1)H (N) temperature coefficients in invisible protein states by relaxation dispersion NMR spectroscopy.

Measuring (1)H (N) temperature coefficients in invisible protein states by relaxation dispersion NMR spectroscopy.

J Biomol NMR. 2011 Mar 18;

Authors: Bouvignies G, Vallurupalli P, Cordes MH, Hansen DF, Kay LE

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.

PMID: 21424227 [PubMed - as supplied by publisher]



Source: PubMed