J. Biol. Chem., Vol. 268, Issue 35, 26049-26051, 12, 1993
Identification of the peptide binding domain of hsc70. 18-Kilodalton fragment located immediately after ATPase domain is sufficient for high affinity binding
TF Wang, JH Chang and C Wang
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
Recombinant hsc70, a purified glutathione S-transferase (GST) fusion
protein containing the C-terminal domain of hsc70 (GST-Ct), and an internal
18-kDa polypeptide located immediately after the 44-kDa ATPase domain of
hsc70 were investigated for their peptide binding properties. The
dissociation constants of the S-peptide for native hsc70 (Kd = 5-8 microM),
GST-Ct (Kd = 6.5 microM), and the 18-kDa fragment (Kd = 8.1 microM) are
virtually identical. In addition, polylysine and (Pro-Pro- Gly)5 do not
show high affinity toward hsc70, GST-Ct, and the 18-kDa fragment, whereas
peptide GT4 and P3a show comparably high affinity toward these
polypeptides. These observations indicate that the peptide binding domain
of hsc70 is confined in the internal 18-kDa fragment.