Electrochemical evidence for the molten globule states of cytochrome c induced by N-alkyl sulfates at low concentrations.
The molten globule state (MG) of cytochrome c is the major intermediate of protein folding. The formation of MG state of cytochrome c is induced by n-alkyl sulfates such as sodium octyl sulfate (SOS), sodium dodecyl sulfate (SDS), and sodium tetradecyl sulfate (STS). The folding state of cytochrome c was monitored using circular dichroism (CD), isothermal titration calorimetry (ITC) and partial specific volumes. To explore a new approach for characterizing the MG conformation, cyclic voltametric studies of n-alkyl sulfates induced transition at acidic pH of cytochrome c (unfolded state, U) was carried out. Here, we have used a cystein-modified gold electrode, which is effective for direct rapid electron transfer to cytochrome c even in acid solutions, to directly observe electrochemistry in native (N) cytochrome c. Our results show that the extent of electron transfer is increased for U --> MG, and also the easiness of electron transferring occurred from MG --> N transition. Thus we demonstrate that the MG state of cytochrome c, induced by n-alkyl sulfates as salts with hydrophobic chains (hydrophobic salts), with different compactness reaches to near identical amount of electron transferring as N state.
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. moosavi@ut.ac.ir
A A
AA
Moosavi-Movahedi
J
J
Chamani
H
H
Ghourchian
H
H
Shafiey
C M
CM
Sorenson
N
N
Sheibani
D000818:Animals; D002151:Calorimetry; D002942:Circular Dichroism; D003574:Cytochrome c Group / Q000737:chemistry*; D004563:Electrochemistry; D006736:Horses; D009206:Myocardium / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D013463:Sulfuric Acid Esters / Q000737:chemistry*
D003574:Cytochrome c Group; D013463:Sulfuric Acid Esters