Human Hsp60 with its mitochondrial import signal occurs in solution as heptamers and tetradecamers remarkably stable over a wide range of concentrations.
It has been established that Hsp60 can accumulate in the cytosol in various pathological conditions, including cancer and chronic inflammatory diseases. Part or all of the cytosolic Hsp60 could be naïve, namely, bear the mitochondrial import signal (MIS), but neither the structure nor the in solution oligomeric organization of this cytosolic molecule has still been elucidated. Here we present a detailed study of the structure and self-organization of naïve cytosolic Hsp60 in solution. Results were obtained by different biophysical methods (light and X ray scattering, single molecule spectroscopy and hydrodynamics) that all together allowed us to assay a wide range of concentrations of Hsp60. We found that Naïve Hsp60 in aqueous solution is assembled in very stable heptamers and tetradecamers at all concentrations assayed, without any trace of monomer presence.
Institute of Biophysics, National Research Council, Palermo, Italy.
Silvia
S
Vilasi
Institute of Biophysics, National Research Council, Palermo, Italy.
Rita
R
Carrotta
Institute of Biophysics, National Research Council, Palermo, Italy.
Maria Rosalia
MR
Mangione
Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy; Euro-Mediterranean Institute of Science and Technology, Palermo, Italy.
Claudia
C
Campanella
Institute of Biophysics, National Research Council, Palermo, Italy.
Fabio
F
Librizzi
Institute of Biophysics, National Research Council, Palermo, Italy.
Loredana
L
Randazzo
Institute of Biophysics, National Research Council, Palermo, Italy.
Vincenzo
V
Martorana
Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy; Euro-Mediterranean Institute of Science and Technology, Palermo, Italy.
Antonella
A
Marino Gammazza
Department of Life and Environmental Sciences and National Interuniversity Consortium for the Physical Sciences of Matter, Marche Polytechnic University, Ancona, Italy.
Maria Grazia
MG
Ortore
Institute of Biosciences and Bioresources, National Research Council, Napoli, Italy.
Annalisa
A
Vilasi
Institute of Biosciences and Bioresources, National Research Council, Napoli, Italy.
Gabriella
G
Pocsfalvi
Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy.
Giosalba
G
Burgio
Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy.
Davide
D
Corona
Institute of Biophysics, National Research Council, Palermo, Italy; Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy.
Antonio
A
Palumbo Piccionello
Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy.
Giovanni
G
Zummo
Institute of Biophysics, National Research Council, Palermo, Italy.
Donatella
D
Bulone
Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology, Columbus Center, Baltimore, Maryland, United States of America.
Everly
E
Conway de Macario
Euro-Mediterranean Institute of Science and Technology, Palermo, Italy; Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology, Columbus Center, Baltimore, Maryland, United States of America.
Alberto J L
AJ
Macario
Institute of Biophysics, National Research Council, Palermo, Italy.
Pier Luigi
PL
San Biagio
Institute of Biophysics, National Research Council, Palermo, Italy; Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy; Euro-Mediterranean Institute of Science and Technology, Palermo, Italy.
Francesco
F
Cappello
D000251:Adenosine Triphosphatases / Q000737:chemistry; D002474:Cell-Free System; D018834:Chaperonin 60 / Q000737:chemistry*; D003600:Cytosol / Q000737:chemistry; D006801:Humans; D006868:Hydrolysis; D007249:Inflammation; D008928:Mitochondria / Q000737:chemistry*; D024101:Mitochondrial Proteins / Q000737:chemistry*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
D018834:Chaperonin 60; C060293:HSPD1 protein, human; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases