Alternate succession of steps can lead to the folding of a multidomain oligomeric protein.
The beta 2 subunit of Escherichia coli tryptophan synthase can be either unfolded in 6 M guanidine, or extensively denatured at acidic pH. These two denatured forms of beta 2 have different circular dichroism spectra and thus correspond to distinct physical states. Here we compare the folding pathways of these two different denatured forms of beta chains. We describe the kinetics of regain of a variety of physical, functional, and immunochemical signals characteristic of six successive steps previously identified on the folding pathway of guanidine unfolded beta 2. It is shown that whereas identical molecular events occur with the same kinetics, the two folding pathways are different, and involve different structural intermediates.
Murry-Brelier
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A
Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France.
Goldberg
M E
ME
D004735:Energy Transfer; D004926:Escherichia coli / Q000201:enzymology; D005453:Fluorescence; D007700:Kinetics; D011487:Protein Conformation; D011489:Protein Denaturation; D012995:Solubility; D014367:Tryptophan Synthase
D014367:Tryptophan Synthase