Guiding strand passage: DNA-induced movement of the gyrase C-terminal domains defines an early step in the supercoiling cycle |
| |
Authors: | Lanz Martin A Klostermeier Dagmar |
| |
Affiliation: | University of Basel, Biozentrum, Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. |
| |
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. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|