The reconstitution of unfolded myoglobin with hemin dicyanide is not accelerated by fly-casting.
This study explores how the kinetics of a coupled folding/binding reaction depend on the initial conformation of the protein. Stopped-flow spectroscopy is used to monitor the reaction of apo-myoglobin (aMb) with hemin dicyanide at pH 7.2. Different initial aMb conformations are tested. In the case of acid-denatured aMb, the observed kinetics are consistent with a "fly-casting" scenario [Shoemaker et al., Proc. Natl. Acad. Sci. USA 97 (2000) 8868-8873]. However, the formation of a compact complex proceeds more rapidly in the case of prefolded aMb. This finding is opposite to what would be expected based on predictions of the fly-casting model.
Crespin
Marcelo O
MO
Department of Chemistry, The University of Western Ontario, London, Ont., Canada N6A 5B7.
Boys
Brian L
BL
Konermann
Lars
L
D003486:Cyanides / Q000737:chemistry; D006427:Hemin / Q000737:chemistry*; D007700:Kinetics; D009211:Myoglobin / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D013050:Spectrometry, Fluorescence
D003486:Cyanides; D009211:Myoglobin; C496336:hemin dicyanide; D006427:Hemin