Purification of a 38-kDa Protein from Rabbit Reticulocyte Lysate Which Promotes Protein Renaturation by Heat Shock Protein 70 and Its Identification as δ-Aminolevulinic Acid Dehydratase and as a Putative DnaJ Protein

摘要: We reported recently that a rabbit reticulocyte 66-kDa protein (termed RF-hsp 70 by our laboratory and p60 hop others) functions as hsp recycling markedly enhances the renaturation of luciferase (Gross, M., Hessefort, S. (1996) J. Biol. Chem. 271, 16833-16841). In this report, we confirm ability to promote conversion 70. ADP 70.ATP, thus enhancing folding activity 70, is caused purified not trace DnaJ/hsp 40 contaminant. To determine relationship between heat shock family, which also 38-kDa from lysate based upon its stimulate Partial amino acid sequencing has indicated, unexpectedly, it enzyme delta-aminolevulinic dehydratase (ALA-D) does contain detectable sequences corresponding family. addition, immunoblot analysis with polyclonal antibody made HeLa cell (from StressGen) confirms ALA-D contains no 40, although present in relatively crude fractions. Rabbit about active converting porphobilinogen Zn2+-dependent other sources. stimulates up 10-fold at concentrations are same or less than absence The effect additive limiting saturating each, and, unlike dissociation 70.ADP presence ATP. renaturation-enhancing may be region near carboxyl terminus sequence homology highly conserved domain DnaJ similar carboxyl-terminal auxilin, DnaJ-like requires for 70-dependent function (Ungewickell, E., Ungewickell, H., Holstein, E. Lindner, R., Prasad, K., Barouch, W., Martin, B., Greene, L. Eisenberg, (1995) Nature 378, 632-635).