CryoEM structure of Hsp104 and its mechanistic implication for protein disaggregation

Proc Natl Acad Sci U S A. 2010 May 4;107(18):8135-40. doi: 10.1073/pnas.1003572107. Epub 2010 Apr 19.


Hsp104 is a ring-forming AAA+ machine that recognizes both aggregated proteins and prion-fibrils as substrates and, together with the Hsp70 system, remodels substrates in an ATP-dependent manner. Whereas the ability to disaggregate proteins is dependent on the Hsp104 M-domain, the location of the M-domain is controversial and its exact function remains unknown. Here we present cryoEM structures of two Hsp104 variants in both crosslinked and noncrosslinked form, in addition to the structure of a functional Hsp104 chimera harboring T4 lysozyme within the M-domain helix L2. Unexpectedly, we found that our Hsp104 chimera has gained function and can solubilize heat-aggregated beta-galactosidase (beta-gal) in the absence of the Hsp70 system. Our fitted structures confirm that the subunit arrangement of Hsp104 is similar to other AAA+ machines, and place the M-domains on the Hsp104 exterior, where they can potentially interact with large, aggregated proteins.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cryoelectron Microscopy
  • Enzyme Stability
  • Heat-Shock Proteins / chemistry*
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism
  • Heat-Shock Proteins / ultrastructure*
  • Models, Molecular
  • Mutation
  • Protein Multimerization
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / chemistry*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / ultrastructure*
  • beta-Galactosidase / metabolism


  • Heat-Shock Proteins
  • Saccharomyces cerevisiae Proteins
  • HsP104 protein, S cerevisiae
  • beta-Galactosidase