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Interaction of human recombinant αA‐ and αB‐crystallins with early and late unfolding intermediates of citrate synthase on its thermal denaturation
Author(s) -
Rajaraman K,
Raman B,
Ramakrishna T,
Rao Ch.Mohan
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02451-6
Subject(s) - citrate synthase , chemistry , atp synthase , chaperone (clinical) , biochemistry , crystallin , enzyme , population , biophysics , biology , medicine , demography , pathology , sociology
We have investigated the role of recombinant human αA‐ and αB‐crystallins in the heat‐induced inactivation and aggregation of citrate synthase. Homo‐multimers of both αA‐ and αB‐crystallins confer protection against heat‐induced inactivation in a concentration‐dependent manner and also prevent aggregation. Interaction of crystallins with early unfolding intermediates of citrate synthase reduces their partitioning into aggregation‐prone intermediates. This appears to result in enhanced population of early unfolding intermediates that can be reactivated by its substrate, oxaloacetate. Both these homo‐multimers do not form a stable complex with the early unfolding intermediates. However, they can form a soluble, stable complex with aggregation‐prone late unfolding intermediates. This soluble complex formation prevents aggregation. Thus, it appears that the chaperone activity of α‐crystallin involves both transient and stable interactions depending on the nature of intermediates on the unfolding pathway; one leads to reactivation of the enzyme activity while the other prevents aggregation.