The substrate recognition mechanisms in chaperonins

J Mol Recognit. Mar-Apr 2004;17(2):85-94. doi: 10.1002/jmr.654.

Abstract

Chaperonins are a family of proteins devoted to assisting the folding of other proteins. They are large oligomers assembled into ring structures that enclose a cavity in which folding takes place. For this process to occur, the chaperonin must first recognize and interact with the unfolded polypeptide, then undergo a conformational change upon nucleotide binding that results in the closure of the cavity which in turn mediates the folding reaction inside the cavity. Although this general mechanism seems to apply to every chaperonin studied so far, there exist two different modes of interaction between the chaperonin and the substrate. The first occurs mainly through the interaction between the exposed hydrophobic residues of the unfolded polypeptides and those of the chaperonin substrate binding site, as elucidated for the chaperonin GroEL from E. coli. The second type of mechanism has been described so far only for the cytosolic chaperonin CCT (Chaperonin Containing TCP-1) and here the interaction seems to be of a more specific nature, involving charged and polar residues in both the chaperonin and the substrate, which interacts with CCT in a structured, quasi-native conformation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Actins / metabolism
  • Amino Acid Sequence
  • Animals
  • Archaeal Proteins / metabolism
  • Chaperonin Containing TCP-1
  • Chaperonins / chemistry*
  • Chaperonins / metabolism*
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Molecular Sequence Data
  • Protein Binding
  • Protein Folding
  • Substrate Specificity
  • Thermosomes
  • Tubulin / metabolism

Substances

  • Actins
  • Archaeal Proteins
  • Tubulin
  • Chaperonin Containing TCP-1
  • Chaperonins
  • Thermosomes