Split conformation of Chaetomium thermophilum Hsp104 disaggregase

Structure. 2021 Jul 1;29(7):721-730.e6. doi: 10.1016/j.str.2021.02.002. Epub 2021 Mar 1.


Hsp104 and its bacterial homolog ClpB form hexameric ring structures and mediate protein disaggregation. The disaggregated polypeptide is thought to thread through the central channel of the ring. However, the dynamic behavior of Hsp104 during disaggregation remains unclear. Here, we reported the stochastic conformational dynamics and a split conformation of Hsp104 disaggregase from Chaetomium thermophilum (CtHsp104) in the presence of ADP by X-ray crystallography, cryo-electron microscopy (EM), and high-speed atomic force microscopy (AFM). ADP-bound CtHsp104 assembles into a 65 left-handed spiral filament in the crystal structure at a resolution of 2.7 Å. The unit of the filament is a hexamer of the split spiral structure. In the cryo-EM images, staggered and split hexameric rings were observed. Further, high-speed AFM observations showed that a substrate addition enhanced the conformational change and increased the split structure's frequency. Our data suggest that split conformation is an off-pathway state of CtHsp104 during disaggregation.

Keywords: Hsp104; molecular chaperone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism*
  • Chaetomium / chemistry
  • Chaetomium / metabolism*
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • Fungal Proteins / chemistry
  • HSP40 Heat-Shock Proteins / chemistry*
  • HSP40 Heat-Shock Proteins / metabolism*
  • Microscopy, Atomic Force
  • Models, Molecular
  • Protein Aggregates
  • Protein Binding
  • Protein Conformation
  • Protein Domains
  • Protein Multimerization


  • Fungal Proteins
  • HSP40 Heat-Shock Proteins
  • Protein Aggregates
  • Adenosine Diphosphate

Supplementary concepts

  • Chaetomium thermophilum