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Chaperone Function of Rat Lens α‐Crystallin
Author(s) -
Ho Yuh,
Hsu MingChing,
Huang FuYung
Publication year - 1998
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199800045
Subject(s) - crystallin , chemistry , chaperone (clinical) , protein subunit , size exclusion chromatography , biophysics , urea , fluorescence , biochemistry , medicine , physics , pathology , quantum mechanics , biology , gene , enzyme
Abstract A solution of γ‐crystallin became turbid upon beating at 65 °C for 30 minutes; however, addition of α‐crystallin suppressed this thermal aggregation. It was found the effective chaperone function could be achieved with the molar ratio of α/γ greater than 1/20. In terms of crystallin subunit, five molecular α‐crystallin subunits could afford chaperone for one molecular γ‐crystallin. The gel filtration profile of the sample solution, containing α‐ and γ‐crystallins and preincubation at 65 °C for 30 minutes, showed complex formation between α‐ and γ‐crystallins, indicating α‐crystallin was bound to thermally denatured γ‐crystallin. A 1‐anilinonaphthalene‐8‐sulfonic acid (ANS) fluorescence study showed that α‐crystallin has more hydrophobic regions exposed after thermal incubation. In the presence of urea, both the α‐crystallin chaperone activity and the ANS fluorescence intensity decreased. Accordingly, hydrophobic regions of α‐crystallin play an indispensible role in its chaperone activity.