Formation in vitro of complexes between an abnormal fusion protein and the heat shock proteins from Escherichia coli and yeast mitochondria.

摘要: Heat shock proteins (HSPs) of the Hsp70 and GroEL families associate with a variety cell in vivo. However, formation such complexes has not been systematically studied. A 31-kDa fusion protein (CRAG), which contains 12 residues cro repressor, truncated A, 14 beta-galactosidase, when expressed Escherichia coli, was found DnaK, GrpE, protease La, GroEL. When an E. coli extract containing CRAG applied to affinity column CRAG, GroEL, GrpE were selectively bound. These HSPs did bind normal column. fraction could be eluted from ATP but nonhydrolyzable analog. The ATP-dependent release DnaK also required Mg2+, dissociated alone. binding independent events, DnaK. Inactivation DnaJ, GroES affect association or dissociation CRAG. 10(-6) M ATP, 10(-4) for release. This approach allows one-step purification these isolation homologs yeast mitochondria. Competition experiments oligopeptide fragments showed that interact different sites on cro-derived domain DnaK-binding site.