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

作者：Bouvignies Guillaume; Vallurupalli Pramodh; Cordes Matthew H J; Hansen D Flemming; Kay Lewis E^*

来源：Journal of Biomolecular NMR, 2011, 50(1): 13-18.

DOI：10.1007/s10858-011-9498-0

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

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 2.5A degrees 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.

• 出版日期2011-5