2rgr
From Proteopedia
Topoisomerase IIA bound to G-segment DNA
Overview
Type II topoisomerases disentangle DNA to facilitate chromosome segregation, and represent a major class of therapeutic targets. Although these enzymes have been studied extensively, a molecular understanding of DNA binding has been lacking. Here we present the structure of a complex between the DNA-binding and cleavage core of Saccharomyces cerevisiae Topo II (also known as Top2) and a gate-DNA segment. The structure reveals that the enzyme enforces a 150 degrees DNA bend through a mechanism similar to that of remodelling proteins such as integration host factor. Large protein conformational changes accompany DNA deformation, creating a bipartite catalytic site that positions the DNA backbone near a reactive tyrosine and a coordinated magnesium ion. This configuration closely resembles the catalytic site of type IA topoisomerases, reinforcing an evolutionary link between these structurally and functionally distinct enzymes. Binding of DNA facilitates opening of an enzyme dimerization interface, providing visual evidence for a key step in DNA transport.
About this Structure
2RGR is a Protein complex structure of sequences from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Structural basis for gate-DNA recognition and bending by type IIA topoisomerases., Dong KC, Berger JM, Nature. 2007 Dec 20;450(7173):1201-5. PMID:18097402 Page seeded by OCA on Sun May 4 16:53:17 2008
