Premium
Redox‐regulated chaperone function and conformational changes of Escherichia coli Hsp33
Author(s) -
Raman B,
Siva Kumar L.V,
Ramakrishna T,
Mohan Rao Ch
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)02074-9
Subject(s) - circular dichroism , chaperone (clinical) , chemistry , escherichia coli , biophysics , redox , conformational change , crystallography , oxidative phosphorylation , heat shock protein , stereochemistry , biochemistry , biology , inorganic chemistry , medicine , pathology , gene
We have studied the chaperone activity and conformation of Escherichia coli heat shock protein (Hsp)33, whose activity is known to be switched on by oxidative conditions. While oxidized Hsp33 completely prevents the heat‐induced aggregation of ζ‐crystallin at 42°C at a ratio of 1:1 (w/w), the reduced form exhibits only a marginal effect on the aggregation. Far UV–circular dichroism (CD) spectra show that reduced Hsp33 contains a significant α‐helical component. Oxidation results in significant changes in the far UV–CD spectrum. Near UV–CD spectra show changes in tertiary structural packing upon oxidation. Polarity‐sensitive fluorescent probes report enhanced hydrophobic surfaces in the oxidized Hsp33. Our studies show that the oxidative activation of the chaperone function of Hsp33 involves observable conformational changes accompanying increased exposure of hydrophobic pockets.