Catalysis of amide proton exchange by the molecular chaperones GroEL and SecB.
Hydrogen-deuterium exchange of 39 amide protons of Bacillus amyloliquefaciens ribonuclease (barnase) was analyzed by two-dimensional nuclear magnetic resonance in the presence of micromolar concentrations of the molecular chaperones GroEL and SecB. Both chaperones bound to native barnase under physiological conditions and catalyzed exchange of deeply buried amide protons with solvent. Such exchange required complete unfolding of barnase, which occurred in the complex with the chaperones. Subsequent collapse of unfolded barnase to the exchange-protected folding intermediate was markedly slowed in the presence of GroEL or SecB. Thus, both chaperones have the potential to correct misfolding in proteins by annealing.
Zahn
R
R
Department of Chemistry, University of Cambridge, UK.
Perrett
S
S
Stenberg
G
G
Fersht
A R
AR
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000577:Amides; D001426:Bacterial Proteins / Q000378:metabolism*; D002384:Catalysis; D018834:Chaperonin 60 / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D018832:Molecular Chaperones / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011522:Protons; D012260:Ribonucleases / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
D000577:Amides; D001426:Bacterial Proteins; D018834:Chaperonin 60; D018832:Molecular Chaperones; D011522:Protons; C057842:SecB protein, Bacteria; D000244:Adenosine Diphosphate; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease