Nick Induced Dynamics in Supercoiled DNA Facilitates the Protein Target Search Process
Sangeeta1, Arnab Bhattacherjee1
1School of Computational & Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
The Journal of Physical Chemistry. B
|August 15, 2024
Summary
DNA nicks release supercoiled DNA stress through writhing and twisting motions, increasing linking number. This enhances protein search dynamics, speeding up transcription by facilitating DNA-protein communication.
Area of Science:
- Molecular Biology
- Biophysics
- Computational Biology
Background:
- Supercoiled DNA accumulates torsional stress, impacting transcriptional machinery.
- DNA nicks are known to alleviate this stress, but their precise role in protein dynamics is unclear.
Purpose of the Study:
- To elucidate the molecular mechanisms by which DNA nicks release stress.
- To investigate the impact of nicks on protein search dynamics crucial for transcription initiation and elongation.
Main Methods:
- Extensive computer simulations were employed to model DNA nicking and its effects.
- Analysis focused on DNA writhing, twisting, linking number changes, and torsional dynamics.
Main Results:
- DNA nicks release intramolecular stress via writhing and twisting, leading to a step-like increase in linking number.
- Nicked supercoiled DNA exhibits enhanced torsional dynamics and faster conformational changes.
- Protein diffusion on nicked DNA is accelerated due to improved DNA-protein communication via juxtaposition site dynamics.
Conclusions:
- DNA nicks are crucial for efficient transcription elongation by actively managing torsional stress during RNA polymerase unwinding.
- The study reveals the mechanistic intricacies of how DNA nicks facilitate protein search and DNA unwinding.
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