1A36

TOPOISOMERASE I/DNA COMPLEX

Summary for 1A36

• Entry DOI: 10.2210/pdb1a36/pdb
• Descriptor: DNA (5'-D(*AP*AP*AP*AP*AP*GP*AP*CP*TP*TP*AP*GP*AP*AP*AP*AP*A P*TP*TP*TP*TP*T)- 3'), DNA (5'-D(*AP*AP*AP*AP*AP*TP*TP*TP*TP*TP*CP*TP*AP*AP*GP*TP*C P*TP*TP*TP*TP*T)- 3'), TOPOISOMERASE I, ... (4 entities in total)
• Functional Keywords: complex (isomerase-dna), dna, topoisomerase i, isomerase-dna complex, isomerase/dna
• Biological source: Homo sapiens (human)
• Cellular location: Nucleus, nucleolus: P11387
• Total number of polymer chains: 3
• Total formula weight: 83518.70

Authors

Stewart, L.,Redinbo, M.R.,Qiu, X.,Champoux, J.J.,Hol, W.G.J. (deposition date: 1998-01-29, release date: 1998-08-12, Last modification date: 2024-04-03)

Primary citation

Stewart, L.,Redinbo, M.R.,Qiu, X.,Hol, W.G.,Champoux, J.J.
A model for the mechanism of human topoisomerase I.
Science, 279:1534-1541, 1998

PubMed 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."

PubMed: 9488652
DOI: 10.1126/science.279.5356.1534

Experimental method

X-RAY DIFFRACTION (2.8 Å)