ATP-triggered ADP release from the asymmetric chaperonin GroEL/GroES/ADP7 is not the rate-limiting step of the GroEL/GroES reaction cycle

FEBS Lett. 2010 Mar 5;584(5):951-3. doi: 10.1016/j.febslet.2010.01.021. Epub 2010 Jan 17.

Abstract

The GroEL/GroES protein folding chamber is formed and dissociated by ATP binding and hydrolysis. ATP hydrolysis in the GroES-bound (cis) ring gates entry of ATP into the opposite unoccupied trans ring, which allosterically ejects cis ligands. While earlier studies suggested that hydrolysis of cis ATP is the rate-limiting step of the cycle (t1/2 approximately 10 s), a recent study suggested that ADP release from the cis ring may be rate-limiting (t1/2 approximately 15-20 s). Here we have measured ADP release using a coupled enzyme assay and observed a t1/2 for release of <or=4-5 s, indicating that this is not the rate-limiting step of the reaction cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Chaperonin 10 / genetics
  • Chaperonin 10 / metabolism*
  • Chaperonin 60 / genetics
  • Chaperonin 60 / metabolism*
  • Chaperonins / genetics
  • Chaperonins / metabolism*
  • Hydrolysis
  • Models, Biological
  • Protein Binding
  • Protein Folding

Substances

  • Chaperonin 10
  • Chaperonin 60
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Chaperonins