Nucleotide-Induced Conformational Changes in an Isolated Escherichia coli DNA Polymerase III Clamp Loader SubunitPodobnik, M., Weitze, T.F., O'Donnell, M., Kuriyan, J.
(2003) Structure 11: 253-263
- PubMed: 12623013
- DOI: https://doi.org/10.1016/s0969-2126(03)00027-3
- Primary Citation of Related Structures:
- PubMed Abstract:
Sliding clamps are loaded onto DNA by ATP-driven clamp loader complexes. The structure of the E. coli clamp loader in a nucleotide-free state has been determined previously. We now report crystal structures of a truncated form of the isolated gamma-ATPase subunit, gamma(1-243), of the E. coli clamp loader, in nucleotide-free and bound forms. The gamma subunit adopts a defined conformation when empty, in which the nucleotide binding site is blocked. The binding of either ATPgammaS or ADP, which are shown to bind with equal affinity to gamma(1-243), induces a change in the relative orientation of the two domains such that nucleotides can be accommodated. This change would break one of the gamma:gamma interfaces seen in the empty clamp loader complex, and may represent one step in the activation process.
Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.