Chemical cross-linking of the chloroplast localized small heat-shock protein, Hsp21, and the model substrate citrate synthase.

ABSTRACT: The molecular mechanism whereby the small heat-shock protein (sHsp) chaperones interact with and prevent aggregation of other proteins is not fully understood. We have characterized the sHsp-substrate protein interaction at normal and increased temperatures utilizing a model substrate protein, citrate synthase (CS), widely used in chaperone assays, and a dodecameric plant sHsp, Hsp21, by chemical cross-linking with 3,3'-Dithiobis[sulfosuccinimidylpropionate] (DTSSP) and mass spectrometric peptide mapping. In the absence of CS, the cross-linker captured Hsp21 in dodecameric form, even at increased temperature (47 degrees C). In the presence of equimolar amounts of CS, no Hsp21 dodecamer was captured, indicating a substrate-induced Hsp21 dodecamer dissociation by equimolar amounts of CS. Cro

SUBMITTER: Ahrman E 

PROVIDER: S-EPMC2206695 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature