Crystal structure of a covalent intermediate in DNA cleavage and rejoining by Escherichia coli DNA topoisomerase I.

ABSTRACT: DNA topoisomerases control DNA topology by breaking and rejoining DNA strands via covalent complexes with cleaved DNA substrate as catalytic intermediates. Here we report the structure of Escherichia coli topoisomerase I catalytic domain (residues 2-695) in covalent complex with a cleaved single-stranded oligonucleotide substrate, refined to 2.3-Å resolution. The enzyme-substrate intermediate formed after strand cleavage was captured due to the presence of the D111N mutation. This structure of the covalent topoisomerase-DNA intermediate, previously elusive for type IA topoisomerases, shows distinct conformational changes from the structure of the enzyme without bound DNA and provides detailed understanding of the covalent catalysis required for strand cleavage to take place. The portion of

SUBMITTER: Zhang Z 

PROVIDER: S-EPMC3084087 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature