Thermal unfolding of ribonuclease A in phosphate at neutral pH: deviations from the two-state model.

ABSTRACT: The thermal denaturation of ribonuclease A (RNase A) in the presence of phosphate at neutral pH was studied by differential scanning calorimetry (DSC) and a combination of optical spectroscopic techniques to probe the existence of intermediate states. Fourier transform infrared (FTIR) spectra of the amide I' band and far-uv circular dichroism (CD) spectra were used to monitor changes in the secondary structure. Changes in the tertiary structure were monitored by near-uv CD. Spectral bandshape changes with change in temperature were analyzed using factor analysis. The global unfolding curves obtained from DSC confirmed that structural changes occur in the molecule before the main thermal denaturation transition. The analysis of the far-uv CD and FTIR spectra showed that these lower temperat

SUBMITTER: Stelea SD 

PROVIDER: S-EPMC2374205 | biostudies-literature | 2001 May

REPOSITORIES: biostudies-literature