Folding kinetics of the lipoic acid-bearing domain of human mitochondrial branched chain alpha-ketoacid dehydrogenase complex.
A reversible two-step (native state<-->denatured state) folding mechanism based on equilibrium and stopped flow experiments is proposed for urea denaturation of the lipoyl-bearing domain (hbLBD) of human mitochondrial branched chain alpha-ketoacid dehydrogenase (BCKD) complex. The results from this circular dichroism (CD) and fluorescence study have ruled out populated kinetic or equilibrium intermediates on folding pathway of this beta-barrel domain under experimental conditions. Both studies suggested mono-exponential kinetics without any burst phases. Moreover the thermodynamic parameters DeltaG(H(2)O) and m obtained from the kinetic analysis are consistent with the equilibrium measurements.
Naik
Mandar T
MT
Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan.
Chang
Yu-Chu
YC
Huang
Tai-huang
TH
D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D002942:Circular Dichroism; D006801:Humans; D007658:Ketone Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology*; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism*; D011489:Protein Denaturation; D017510:Protein Folding; D013050:Spectrometry, Fluorescence; D008063:Thioctic Acid / Q000378:metabolism*; D014508:Urea / Q000737:chemistry
D009097:Multienzyme Complexes; D008063:Thioctic Acid; D014508:Urea; D007658:Ketone Oxidoreductases; D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)