Purification and characterization of the 90-kDa heat-shock protein from mammalian tissues

The 90-kDa heat-shock protein (HSP90) has been purified from mammalian tissues, mouse liver and porcine brain, with a good yield by a new method involving hydrophobic chromatography. Mouse liver HSP90 and porcine brain HSP90 were compared with mouse lymphoma HSP90 which was purified from T lymphoma cell line, L5178Y, by a modification of the previously reported method. These three HSP90s were indistinguishable from one another in amino acid composition, one-dimensional peptide mapping, elution pattern of proteolytic fragments (trypsin- or V8-protease-cleaved) in reverse-phase high-performance liquid chromatography, reactivity with the antibody against mouse T lymphoma HSP90 and the ability to bind to F-actin. The amino acid sequences of three portions (total 47 amino acid residues) of lymphoma HSP90 were determined and they were homologous to those of the corresponding portions of Drosophila HSP83A and yeast HSP90. These results suggest that HSP90 is a highly conserved protein during evolution.