PMID:15897198
| Citation |
Ruthenburg, AJ, Graybosch, DM, Huetsch, JC and Verdine, GL (2005) A superhelical spiral in the Escherichia coli DNA gyrase A C-terminal domain imparts unidirectional supercoiling bias. J. Biol. Chem. 280:26177-84 |
|---|---|
| Abstract |
DNA gyrase is unique among type II topoisomerases in that its DNA supercoiling activity is unidirectional. The C-terminal domain of the gyrase A subunit (GyrA-CTD) is required for this supercoiling bias. We report here the x-ray structure of the Escherichia coli GyrA-CTD (Protein Data Bank code 1ZI0). The E. coli GyrA-CTD adopts a circular-shaped beta-pinwheel fold first seen in the Borrelia burgdorferi GyrA-CTD. However, whereas the B. burgdorferi GyrA-CTD is flat, the E. coli GyrA-CTD is spiral. DNA relaxation assays reveal that the E. coli GyrA-CTD wraps DNA inducing substantial (+) superhelicity, while the B. burgdorferi GyrA-CTD introduces a more modest (+) superhelicity. The observation of a superhelical spiral in the present structure and that of the Bacillus stearothermophilus ParC-CTD structure suggests unexpected similarities in substrate selectivity between gyrase and Topo IV enzymes. We propose a model wherein the right-handed ((+) solenoidal) wrapping of DNA around the E. coli GyrA-CTD enforces unidirectional (-) DNA supercoiling. |
| Links |
PubMed Online version:10.1074/jbc.M502838200 |
| Keywords |
Borrelia burgdorferi/metabolism; Crystallography, X-Ray; DNA/chemistry; DNA Gyrase/chemistry; DNA Gyrase/genetics; DNA Topoisomerase IV/chemistry; DNA, Superhelical; Electrons; Escherichia coli/enzymology; Escherichia coli/genetics; Geobacillus stearothermophilus/metabolism; Models, Molecular; Plasmids/metabolism; Protein Conformation; Protein Structure, Secondary; Protein Structure, Tertiary; Static Electricity; Vaccinia virus/enzymology |
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