title: Stability and disassembly properties of human naïve Hsp60 and bacterial GroEL chaperonins.
abstract: Human Hsp60 chaperonin and its bacterial homolog GroEL, in association with the corresponding co-chaperonins Hsp10 and GroES, constitute important chaperone systems promoting the proper folding of several mitochondrial proteins. Hsp60 is also currently described as a ubiquitous molecule with multiple roles both in health conditions and in several diseases. Naïve Hsp60 bearing the mitochondrial import signal has been recently demonstrated to present different oligomeric organizations with respect to GroEL, suggesting new possible physiological functions. Here we present a combined investigation with circular dichroism and small-angle X-ray scattering of structure, self-organization, and stability of naïve Hsp60 in solution in comparison with bacterial GroEL. Experiments have been performed in different concentrations of guanidine hydrochloride, monitoring the dissociation of tetradecamers into heptamers and monomers, until unfolding. GroEL is proved to be more stable with respect to Hsp60, and the unfolding free energy as well as its dependence on denaturant concentration is obtained.
authors.affiliation: Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Ricci
authors.affiliation: Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy. Electronic address: m.g.ortore@univpm.it.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Ortore
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vilasi
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Carrotta
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Maria Rosalia
authors.initials: MR
authors.lastname: Mangione
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Bulone
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Librizzi
authors.affiliation: Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Spinozzi
authors.affiliation: Department STEBICEF, University of Palermo, Palermo, Italy.
authors.forename: Giosalba
authors.initials: G
authors.lastname: Burgio
authors.affiliation: Institute of Inorganic Chemistry, Graz University of Technology, A-8010, Graz, Austria.
authors.forename: Heinz
authors.initials: H
authors.lastname: Amenitsch
authors.affiliation: Biophysics Institute, National Research Council, Palermo 90143, Italy.
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: San Biagio
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D018834:Chaperonin 60 / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D006801:Humans; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism; D055550:Protein Stability; D053838:Scattering, Small Angle; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; C060293:HSPD1 protein, human; D024101:Mitochondrial Proteins
keywords: CD; Denaturation; GroEL; Guanidinium chloride; Hsp60; SAXS