Effect of disulfide crosslinking on thermal transitions and chaperone-like activity of human small heat shock protein HspB1.

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Article

Title:	Effect of disulfide crosslinking on thermal transitions and chaperone-like activity of human small heat shock protein HspB1.
Authors:	Chalova AS; Sudnitsyna MV; Semenyuk PI; Orlov VN; Gusev NB
Publication:	Cell Stress Chaperones. 2014 Nov;19(6):963-72. doi: 10.1007/s12192-014-0520-9. Epub 2014 Jun 5.
PubmedID	24898092
Abstract
Temperature-induced conformational changes of reduced and oxidized HspB1 crosslinked by disulfide bond between single Cys137 of neighboring monomers were analyzed by means of different techniques. Heating of reduced HspB1 was accompanied by irreversible changes of Trp fluorescence, whereas oxidized HspB1 underwent completely reversible changes of fluorescence. Increase of the temperature in the range of 20-70 degrees C was accompanied by self-association of both reduced and oxidized protein. Further increase of the temperature led to formation of heterogeneous mixture of large self-associated complexes of reduced HspB1 and to formation of smaller and less heterogeneous complexes of oxidized HspB1. Heat-induced changes of oligomeric state of reduced HspB1 were only partially reversible, whereas the corresponding changes of oligomeric state of oxidized HspB1 were almost completely reversible. Oxidation resulted in decrease of chaperone-like activity of HspB1. It is concluded that oxidative stress, inducing formation of disulfide bond, can affect stability and conformational mobility of human HspB1.