Dynamic Structural States of ClpB Involved in Its Disaggregation Function

Nat Commun. 2018 Jun 1;9(1):2147. doi: 10.1038/s41467-018-04587-w.

Abstract

The ATP-dependent bacterial protein disaggregation machine, ClpB belonging to the AAA+ superfamily, refolds toxic protein aggregates into the native state in cooperation with the cognate Hsp70 partner. The ring-shaped hexamers of ClpB unfold and thread its protein substrate through the central pore. However, their function-related structural dynamics has remained elusive. Here we directly visualize ClpB using high-speed atomic force microscopy (HS-AFM) to gain a mechanistic insight into its disaggregation function. The HS-AFM movies demonstrate massive conformational changes of the hexameric ring during ATP hydrolysis, from a round ring to a spiral and even to a pair of twisted half-spirals. HS-AFM observations of Walker-motif mutants unveil crucial roles of ATP binding and hydrolysis in the oligomer formation and structural dynamics. Furthermore, repressed and hyperactive mutations result in significantly different oligomeric forms. These results provide a comprehensive view for the ATP-driven oligomeric-state transitions that enable ClpB to disentangle protein aggregates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Endopeptidase Clp / chemistry
  • Endopeptidase Clp / genetics
  • Endopeptidase Clp / metabolism*
  • Heat-Shock Proteins / chemistry
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism*
  • Microscopy, Atomic Force
  • Mutation
  • Protein Aggregates
  • Protein Aggregation, Pathological
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Thermus thermophilus / genetics
  • Thermus thermophilus / metabolism*

Substances

  • Bacterial Proteins
  • Heat-Shock Proteins
  • Protein Aggregates
  • Adenosine Triphosphate
  • Endopeptidase Clp