Folding and self-assembly of the domains of betaB2-crystallin from rat eye lens.
betaB2-Crystallin from vertebrate eye lens forms domain-swapped dimers, with subunits consisting of two all-beta domains connected by an eight-residue extended linker peptide. Topologically, the two domains show great similarity; however, they differ widely in their stability. As shown by urea-induced equilibrium unfolding experiments, the isolated monomeric C-terminal domain is more stable than complete betaB2. In contrast, the N-terminal domain exhibits marginal stability only in its dimeric state; upon subunit dissociation, at low protein concentration, unfolding takes place. The folding and association of intact betaB2 follows a sequential uni-bimolecular mechanism according to N2 <==> 2 I <==> 2U, whereas the isolated domains may be quantitatively described by the two-state model (N <==> U).
Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, D-93040, Germany.
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K
Wieligmann
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EM
Mayr
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R
Jaenicke
D000818:Animals; D003459:Crystallins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D005123:Eye / Q000378:metabolism; D007908:Lens, Crystalline / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D051381:Rats; D013056:Spectrophotometry, Ultraviolet; D038206:beta-Crystallin B Chain / Q000031:analogs & derivatives*
D003459:Crystallins; D038206:beta-Crystallin B Chain; C113634:beta-crystallin B2