1ATR
THREONINE 204 OF THE CHAPERONE PROTEIN HSC70 INFLUENCES THE STRUCTURE OF THE ACTIVE SITE BUT IS NOT ESSENTIAL FOR ATP HYDROLYSIS
Summary for 1ATR
| Entry DOI | 10.2210/pdb1atr/pdb |
| Descriptor | HEAT-SHOCK COGNATE 70 KD PROTEIN, MAGNESIUM ION, PHOSPHATE ION, ... (5 entities in total) |
| Functional Keywords | chaperone protein |
| Biological source | Bos taurus (cattle) |
| Total number of polymer chains | 1 |
| Total formula weight | 43057.54 |
| Authors | O'Brien, M.C.,Mckay, D.B. (deposition date: 1993-08-09, release date: 1993-10-31, Last modification date: 2024-02-07) |
| Primary citation | O'Brien, M.C.,McKay, D.B. Threonine 204 of the chaperone protein Hsc70 influences the structure of the active site, but is not essential for ATP hydrolysis. J.Biol.Chem., 268:24323-24329, 1993 Cited by PubMed Abstract: The chaperone protein Hsc70 is an ATPase of unknown mechanism, although the crystal structure of the 44-kDa ATPase domain has been solved. This structure shows that the hydroxyl of threonine 204 is located close to the gamma-phosphate of ATP, in a position where it might be an intermediate phosphate acceptor in the hydrolysis reaction. We made two point mutations at residue 204 of Hsc70, threonine to valine (T204V) and threonine to glutamic acid (T204E). The wild-type ATPase domain had a Km for ATP of approximately 1 microM; the mutants had Km values of approximately 90 microM. The kcat values for the mutant proteins were also increased. After crystallization, the structures of the T204V and T204E proteins were solved and refined with data to 2.3- and 2.4-A resolution, respectively. The overall tertiary structure of the mutants showed little change from the wild type; however, significant changes were observed in the active site. Analysis of the structures suggested possible reasons for the changes in kinetic constants. Threonine 204 does not seem to be an obligatory intermediate phosphate acceptor in the hydrolysis reaction since the mutants retained appreciable ATPase activity. PubMed: 8226982PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.34 Å) |
Structure validation
Download full validation report
