Summary information and primary citation
- PDB-id
-
1a36;
DSSR-derived features in text and
JSON formats; DNAproDB
- Class
- isomerase-DNA
- Method
- X-ray (2.8 Å)
- Summary
- Topoisomerase i-DNA complex
- Reference
-
Stewart L, Redinbo MR, Qiu X, Hol WG, Champoux JJ (1998):
"A
model for the mechanism of human topoisomerase I."
Science, 279, 1534-1541. doi:
10.1126/science.279.5356.1534.
- Abstract
- 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."
