title: Guiding strand passage: DNA-induced movement of the gyrase C-terminal domains defines an early step in the supercoiling cycle.
abstract: DNA gyrase catalyzes ATP-dependent negative supercoiling of DNA in a strand passage mechanism. A double-stranded segment of DNA, the T-segment, is passed through the gap in a transiently cleaved G-segment by coordinated closing and opening of three protein interfaces in gyrase. T-segment capture is thought to be guided by the C-terminal domains of the GyrA subunit of gyrase that wrap DNA around their perimeter and cause a DNA-crossing with a positive handedness. We show here that the C-terminal domains are in a downward-facing orientation in the absence of DNA, but swing up and rotate away from the gyrase body when DNA binds. The upward movement of the C-terminal domains is an early event in the catalytic cycle of gyrase that is triggered by binding of a G-segment, and first contacts of the DNA with the C-terminal domains, and contributes to T-segment capture and subsequent strand passage.
authors: University of Basel, Biozentrum, Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
authors: Martin A
authors: MA
authors: Lanz
authors: Dagmar
authors: D
authors: Klostermeier
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology; D004247:DNA / Q000378:metabolism; D027081:DNA Gyrase / Q000737:chemistry* / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009038:Motion; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry
chemical_list: D004278:DNA, Superhelical; D021122:Protein Subunits; D004247:DNA; D027081:DNA Gyrase