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1a36
From Proteopedia
| 1a36, resolution 2.80Å () | |||||||||
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| Activity: | DNA topoisomerase, with EC number 5.99.1.2 | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Contents |
TOPOISOMERASE I/DNA COMPLEX
The three-dimensional structure of a 70-kilodalton amino terminally truncated form of human topoisomerase I in complex with a 22-base pair duplex oligonucleotide, determined to a resolution of 2.8 angstroms, reveals all of the structural elements of the enzyme that contact DNA. The linker region that connects the central core of the enzyme to the carboxyl-terminal domain assumes a coiled-coil configuration and protrudes away from the remainder of the enzyme. The positively charged DNA-proximal surface of the linker makes only a few contacts with the DNA downstream of the cleavage site. In combination with the crystal structures of the reconstituted human topoisomerase I before and after DNA cleavage, this information suggests which amino acid residues are involved in catalyzing phosphodiester bond breakage and religation. The structures also lead to the proposal that the topoisomerization step occurs by a mechanism termed "controlled rotation."
A model for the mechanism of human topoisomerase I., Stewart L, Redinbo MR, Qiu X, Hol WG, Champoux JJ, Science. 1998 Mar 6;279(5356):1534-41. PMID:9488652
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
1a36 is a 3 chain structure of Topoisomerase with sequence from Homo sapiens. The January 2006 RCSB PDB Molecule of the Month feature on Topoisomerases by David S. Goodsell is 10.2210/rcsb_pdb/mom_2006_1. Full crystallographic information is available from OCA.
See Also
Reference
- Stewart L, Redinbo MR, Qiu X, Hol WG, Champoux JJ. A model for the mechanism of human topoisomerase I. Science. 1998 Mar 6;279(5356):1534-41. PMID:9488652
- Redinbo MR, Stewart L, Champoux JJ, Hol WG. Structural flexibility in human topoisomerase I revealed in multiple non-isomorphous crystal structures. J Mol Biol. 1999 Sep 24;292(3):685-96. PMID:10497031 doi:10.1006/jmbi.1999.3065
