The oxidative refolding of hen lysozyme and its catalysis by protein disulfide isomerase.
The oxidative refolding of hen lysozyme has been studied by a variety of time-resolved biophysical methods in conjunction with analysis of folding intermediates using reverse-phase HPLC. In order to achieve this, refolding conditions were designed to reduce aggregation during the early stages of the folding reaction. A complex ensemble of relatively unstructured intermediates with on average two disulfide bonds is formed rapidly from the fully reduced protein after initiation of folding. Following structural collapse, the majority of molecules slowly form the four-disulfide-containing fully native protein via rearrangement of a highly native-like, kinetically trapped intermediate, des-[76-94], although a significant population (approximately 30%) appears to fold more quickly via other three-disulfide intermediates. The folding catalyst PDI increases dramatically both yields and rates of lysozyme refolding, largely by facilitating the conversion of des-[76-94] to the native state. This suggests that acceleration of the folding rate may be an important factor in avoiding aggregation in the intracellular environment.
van den Berg
B
B
Oxford Centre for Molecular Sciences, New Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QT, UK.
Chung
E W
EW
Robinson
C V
CV
Mateo
P L
PL
Dobson
C M
CM
D000818:Animals; D002384:Catalysis; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004220:Disulfides; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry*; D010084:Oxidation-Reduction; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D017510:Protein Folding; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D004220:Disulfides; D009113:Muramidase; D019704:Protein Disulfide-Isomerases