title: Glycerol-induced formation of the molten globule from acid-denatured cytochrome c: implication for hierarchical folding.
abstract: At high concentration (98% or higher, v/v), glycerol induces collapse of acid-denatured cytochrome c into a compact state, the G(U) state, showing a molten globule character. The G(U) state possesses a nativelike alpha-helix structure but a tertiary conformation less packed with respect to the native state. The spectroscopic properties of the G(U) state closely resemble those of the molten globule stabilized by the organic solvent from the native protein (called the G(N) state), indicating that glycerol can stabilize the molten globule of cytochrome c either from the native or the acid-denatured protein. The G(U) and the G(N) states show spectroscopic (and, thus, structural) properties and stabilities comparable to those of molten globules stabilized by different effectors, despite the fact that the mechanisms involved in the molten globule formation may significantly differ. This implies in cytochrome c a hierarchy for the rupture (native-to-molten globule) or the formation (unfolded-to-molten globule) of intramolecular interactions leading to the stabilization of the molten globule state of the protein, independently from the effector responsible for the structural transition, in accord with the sequential model proposed by Englander and collaborators.
authors.affiliation: Università di Roma Tor Vergata, Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Bongiovanni
authors.forename: Federica
authors.initials: F
authors.lastname: Sinibaldi
authors.forename: Tommaso
authors.initials: T
authors.lastname: Ferri
authors.forename: Roberto
authors.initials: R
authors.lastname: Santucci
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D003574:Cytochrome c Group / Q000737:chemistry* / Q000378:metabolism*; D005990:Glycerol / Q000737:chemistry*; D006736:Horses; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary
chemical_list: D003574:Cytochrome c Group; D005990:Glycerol