EFFECT OF HEAT-INDUCED STRUCTURAL PERTURBATION OF SECONDARY AND TERTIARY STRUCTURES ON THE CHAPERONE ACTIVITY OF ALPHA-CRYSTALLIN

Citation
Js. Lee et al., EFFECT OF HEAT-INDUCED STRUCTURAL PERTURBATION OF SECONDARY AND TERTIARY STRUCTURES ON THE CHAPERONE ACTIVITY OF ALPHA-CRYSTALLIN, Biochemical and biophysical research communications, 237(2), 1997, pp. 277-282
Citations number
26
Categorie Soggetti
Biology,Biophysics
ISSN journal
0006291X
Volume
237
Issue
2
Year of publication
1997
Pages
277 - 282
Database
ISI
SICI code
0006-291X(1997)237:2<277:EOHSPO>2.0.ZU;2-X
Abstract
alpha-Crystallin, a major protein of the lens, is known to have chaper one activity to protect other proteins against thermal aggregation. He at-induced structural change of alpha-crystallin was previously shown to increase its chaperone activity. In this report, we studied the the rmal reversibility of alpha-crystallin and the effect of change in sec ondary structure on its chaperone function in vitro. The heat-induced conformational changes in the aromatic region of near-UV CD spectra sh owed only a small degree of reversibility. The structural transitions from 50 to 70 degrees C were largely reversible if the incubation time was short. However, the protective ability to inhibit thermal aggrega tion of alcohol dehydrogenase by alpha-crystallin was essentially simi lar at 48 and 70 degrees C, Under long-term heating at high temperatur es, there was a time-dependent irreversibility of structural change in alpha-crystallin as revealed by CD spectroscopy. Such denatured alpha -crystallin by long-term heating can still preserve its ability to pre vent UV-induced aggregation of gamma-crystallin at room temperature, i ndicating relatively little effect of heat-induced changes in secondar y structure on the chaperone activity of alpha-crystallin. (C) 1997 Ac ademic Press.