Human Hsp60 with its mitochondrial import signal occurs in solution as heptamers and tetradecamers remarkably stable over a wide range of concentrations

PLoS One. 2014 May 15;9(5):e97657. doi: 10.1371/journal.pone.0097657. eCollection 2014.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Cell-Free System
  • Chaperonin 60 / chemistry*
  • Cytosol / chemistry
  • Humans
  • Hydrolysis
  • Inflammation
  • Mitochondria / chemistry*
  • Mitochondrial Proteins / chemistry*
  • Protein Binding
  • Recombinant Proteins / chemistry
  • Scattering, Radiation
  • Spectrometry, Fluorescence

Substances

  • Chaperonin 60
  • HSPD1 protein, human
  • Mitochondrial Proteins
  • Recombinant Proteins
  • Adenosine Triphosphatases

Grant support

This work has been supported by Italian grant FIRB “Future in research” RBFR12SIPT MIND: "Multidisciplinary Investigations for the development of Neuro-protective Drugs". FC and AJLM were partially supported by Euro-Mediterranean Institute of Science and Technology (Italy). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.