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Loading dynamics of a sliding DNA clamp

Journal Article


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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.

Publication Date


  • 2014

Citation


  • Cho, W., Jergic, S., Kim, D., Dixon, N. E. & Lee, J. (2014). Loading dynamics of a sliding DNA clamp. Angewandte Chemie International Edition, 53 (26), 6768-6771.

Scopus Eid


  • 2-s2.0-84903212525

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3095&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2077

Has Global Citation Frequency


Number Of Pages


  • 3

Start Page


  • 6768

End Page


  • 6771

Volume


  • 53

Issue


  • 26

Place Of Publication


  • Germany

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.

Publication Date


  • 2014

Citation


  • Cho, W., Jergic, S., Kim, D., Dixon, N. E. & Lee, J. (2014). Loading dynamics of a sliding DNA clamp. Angewandte Chemie International Edition, 53 (26), 6768-6771.

Scopus Eid


  • 2-s2.0-84903212525

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3095&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2077

Has Global Citation Frequency


Number Of Pages


  • 3

Start Page


  • 6768

End Page


  • 6771

Volume


  • 53

Issue


  • 26

Place Of Publication


  • Germany