Femtosecond study of partially folded states of cytochrome C by solvation dynamics.
Using femtosecond time-resolved fluorescence spectroscopy, it is shown that the solvation dynamics in the two partially folded states (IS' and IS' ') of a protein, cytochrome C, are very different. In the case of IS' (formed by the addition of 2 mM sodium dodecyl sulfate, SDS) almost the entire dynamic solvent shift of coumarin 153 (C153) is captured in a picosecond setup and the contribution of the ultrafast component (0.5 ps) is very small (5%). Solvation dynamics of IS' ' (formed by 2 mM SDS and 5 M urea) displays a major component (47%) of 1.3 ps. This indicates that the structure of IS' ' is much more open and exposed compared to that of IS'. The difference in the dynamics of IS' and IS' ' is attributed to differences in their structure, particularly near the heme region, and the presence of urea in IS' '.
Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
Kalyanasis
K
Sahu
Sudip Kumar
SK
Mondal
Subhadip
S
Ghosh
Durba
D
Roy
Pratik
P
Sen
Kankan
K
Bhattacharyya
D045304:Cytochromes c / Q000737:chemistry*; D017510:Protein Folding; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D014508:Urea / Q000737:chemistry
D012997:Solvents; D012967:Sodium Dodecyl Sulfate; D014508:Urea; D045304:Cytochromes c