Crystal structures of human topoisomerase I in covalent and noncovalent complexes with DNA.Redinbo, M.R., Stewart, L., Kuhn, P., Champoux, J.J., Hol, W.G.
(1998) Science 279: 1504-1513
- PubMed: 9488644
- DOI: https://doi.org/10.1126/science.279.5356.1504
- Primary Citation of Related Structures:
- PubMed Abstract:
Topoisomerases I promote the relaxation of DNA superhelical tension by introducing a transient single-stranded break in duplex DNA and are vital for the processes of replication, transcription, and recombination. The crystal structures at 2.1 and 2.5 angstrom resolution of reconstituted human topoisomerase I comprising the core and carboxyl-terminal domains in covalent and noncovalent complexes with 22-base pair DNA duplexes reveal an enzyme that "clamps" around essentially B-form DNA. The core domain and the first eight residues of the carboxyl-terminal domain of the enzyme, including the active-site nucleophile tyrosine-723, share significant structural similarity with the bacteriophage family of DNA integrases. A binding mode for the anticancer drug camptothecin is proposed on the basis of chemical and biochemical information combined with these three-dimensional structures of topoisomerase I-DNA complexes.
Biomolecular Structure Center and Department of Biological Structure, Box 357742, School of Medicine, University of Washington, Seattle, WA 98195, USA.