Equilibrium and Kinetic folding properties of alpha-helical Greek key protein domains
Title: | Equilibrium and Kinetic folding properties of alpha-helical Greek key protein domains |
Author: | Chen, Yun-Ru |
Advisors: | Carla Mattos, Committee Member A. Clay Clark, Committee Chair Harold Swaisgood, Committee Member Dennis T. Brown, Committee Member |
Abstract: | I have characterized the equilibrium and kinetic folding properties of members of alpha-helical Greek key protein domain, caspase recruitment domains of RICK (RICK-CARD) and procaspase-1 (Pro-1-CARD). At equilibrium, folding of both RICK-CARD and Pro-1-CARD is well described by a two-state mechanism representing the native and unfolded ensembles. The proteins are marginally stable,with the Gibbs free energy of 3.0 and 1.1 kcal/mol and m-values of 1.27 and 0.68 kcal/mol/M for RICK-CARD and Pro-1-CARD, respectively (30 mM Tris-HCl, pH 8, 1 mM DTT, 25 degree Celsius). The folding pathways of RICK-CARD are complex and contain at least two or three non-native conformations. The major folding event of RICK-CARD has a folding rate constant of 30 s⁻¹. Studies on seven mutants of RICK-CARD suggest that the three prolyl residues contribute to its structural stability and folding complexity. The folding of Pro-1-CARD is different than that of RICK-CARD. The folding and unfolding kinetics of Pro-1-CARD are fast but with kinetically trapped intermediates present, which appear to be similar to that of RICK-CARD. The work suggests that different alpha-helical Greek key protein domains fold differently but may share some similar folding pathways. |
Date: | 2003-11-13 |
Degree: | PhD |
Discipline: | Biochemistry |
URI: | http://www.lib.ncsu.edu/resolver/1840.16/3718 |
Files in this item
Files | Size | Format | View |
---|---|---|---|
etd.pdf | 6.301Mb |
View/ |