Abstract
Sliding DNA clamps are loaded at a ss/dsDNA junction by a clamp loader that depends on ATP binding for clamp opening. Sequential ATP hydrolysis results in closure of the clamp so that it completely encircles and diffuses on dsDNA. We followed events during loading of an E. coli β clamp in real time by using single-molecule FRET (smFRET). Three successive FRET states were retained for 0.3 s, 0.7 s, and 9 min: Hydrolysis of the first ATP molecule by the γ clamp loader resulted in closure of the clamp in 0.3 s, and after 0.7 s in the closed conformation, the clamp was released to diffuse on the dsDNA for at least 9 min. An additional single-molecule polarization study revealed that the interfacial domain of the clamp rotated in plane by approximately 8° during clamp closure. The single-molecule polarization and FRET studies thus revealed the real-time dynamics of the ATP-hydrolysis-dependent 3D conformational change of the β clamp during loading at a ss/dsDNA junction.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6768-6771 |
| Number of pages | 4 |
| Journal | Angewandte Chemie International Edition |
| Volume | 53 |
| Issue number | 26 |
| DOIs | |
| State | Published - May 22 2014 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: This research was supported by the National Research Foundation (NRF) of Korea and was funded by the Ministry of Education, Science, and Technology (MEST; Grants No. 2011-0013901 and No. 2010-0019706), by the Australian Research Council (DP0877658), and by an FIC Award from the King Abdullah University of Science and Technology (Saudi Arabia).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.