No evidence for a forced-unfolding mechanism during ATP/GroES binding to substrate-bound GroEL: no observable protection of metastable Rubisco intermediate or GroEL-bound Rubisco from tritium exchange

FEBS Lett. 2005 Feb 14;579(5):1183-6. doi: 10.1016/j.febslet.2005.01.013.

Abstract

In tritium-hydrogen exchange experiments, the large GroEL substrate Rubisco was unfolded and exchanged in urea/acid/tritiated water, then diluted into either protic buffer or protic buffer containing GroEL. The respective Rubisco metastable folding intermediate or Rubisco-GroEL binary complex was then separated from residual tritium after varying times of exchange by centrifugation through P-10 or G-25 resin. No significant tritium was recovered in either case, in contrast to an earlier report. Thus, although the earlier-proposed forced unfolding mechanism for the action of GroEL on a bound polypeptide, occurring during ATP/GroES binding, remains an attractive hypothesis, the data here do not provide any indication that it is involved in the folding of Rubisco.

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Chaperonin 10 / metabolism*
  • Chaperonin 60 / metabolism*
  • Protein Denaturation
  • Protein Folding*
  • Rhodospirillum rubrum / metabolism*
  • Ribulose-Bisphosphate Carboxylase / metabolism*
  • Tritium / metabolism*

Substances

  • Chaperonin 10
  • Chaperonin 60
  • Tritium
  • Adenosine Triphosphate
  • Ribulose-Bisphosphate Carboxylase