Dissociation of human alphaB-crystallin aggregates by thiocyanate is structurally and functionally reversible.
Conformational modifications and changes in the aggregation state of human alphaB-crystallin were investigated at different concentrations of SDS, KBr, urea, and NH4SCN and at different temperatures. Intrinsic fluorescence measurements indicated complete and reversible unfolding of the protein at 2 M NH4SCN, whereas the concentration of urea required for complete and irreversible unfolding was 6 M. Gel permeation chromatography indicated almost complete dissociation of the micelle-like aggregate of alphaB-crystallin in 2 M NH4SCN, but only partial dissociation into large-sized aggregates in 6 M urea. Thiocyanate-treated alphaB-crystallin recovered its chaperone-like activity upon dilution of the dissociating agent, whereas the urea-treated protein did not.
Maida
V
V
Dipartimento di Chimica, Università degli Studi di Sassari, Italy.
Bennardini
F
F
Bonomi
F
F
Ganadu
M L
ML
Iametti
S
S
Mura
G M
GM
D003459:Crystallins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D005453:Fluorescence; D006801:Humans; D018832:Molecular Chaperones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011487:Protein Conformation; D013861:Thiocyanates / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry
D003459:Crystallins; D018832:Molecular Chaperones; D013861:Thiocyanates; D014364:Tryptophan