Folding-unfolding and aggregation-dissociation of bovine alpha-crystallin subunits; evidence for unfolding intermediates of the alpha A subunits.
The aggregation and dissociation behavior of bovine alpha-crystallin as well as the folding and unfolding of its subunits were investigated by equilibrium studies using tryptophan fluorescence measurements and two isoelectric focusing techniques, viz. isoelectric focusing across a urea gradient and isoelectric focusing in two dimensions with different concentrations of urea. It was found that the alpha B chains lose their ability to aggregate and start unfolding at a lower concentration of urea than the alpha A chains. Equilibrium intermediates were found upon unfolding or refolding of alpha A subunits, which can be explained by a two-domain organization of these molecules.
van den Oetelaar
P J
PJ
Department of Biochemistry, University of Nijmegen, The Netherlands.
Hoenders
H J
HJ
D000818:Animals; D002417:Cattle; D003459:Crystallins / Q000648:ultrastructure*; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D014364:Tryptophan; D014508:Urea / Q000494:pharmacology
D003459:Crystallins; D014364:Tryptophan; D014508:Urea