Abstract
Folding of cytochrome c from its low pH guanidine hydrochloride (Gdn- HCI) denatured state revealed a new intermediate, a five-coordinate high spin species with a water molecule coordinated to the heme. Incorporation of this five-coordinated intermediate into the previously reported ligand exchange model can quantitatively account for the observed folding kinetics. In this new model, unfolded cytochrome c is converted to its native structure through an obligatory folding intermediate, the histidine-water coordination state, whereas the five-coordinate state and a bis-histidine state are off-pathway intermediates. When the concentration of Gdn-HCI in the refolding solution was increased, an acceleration of the conversion from the bis-histidine coordinated state to the histidine-water coordinated state was observed, demonstrating that the reaction requires unfolding of the mis-organized polypeptide structure associated with the bis-histidine state.
Original language | English (US) |
---|---|
Pages (from-to) | 222-228 |
Number of pages | 7 |
Journal | Nature Structural Biology |
Volume | 5 |
Issue number | 3 |
DOIs | |
State | Published - 1998 |
ASJC Scopus subject areas
- Structural Biology
- Biochemistry
- Genetics