Conserved linear dynamics of single-molecule Brownian motion

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13 Scopus citations


Macromolecular diffusion in homogeneous fluid at length scales greater than the size of the molecule is regarded as a random process. The mean-squared displacement (MSD) of molecules in this regime increases linearly with time. Here we show that non-random motion of DNA molecules in this regime that is undetectable by the MSD analysis can be quantified by characterizing the molecular motion relative to a latticed frame of reference. Our lattice occupancy analysis reveals unexpected sub-modes of motion of DNA that deviate from expected random motion in the linear, diffusive regime. We demonstrate that a subtle interplay between these sub-modes causes the overall diffusive motion of DNA to appear to conform to the linear regime. Our results show that apparently random motion of macromolecules could be governed by non-random dynamics that are detectable only by their relative motion. Our analytical approach should advance broad understanding of diffusion processes of fundamental relevance.
Original languageEnglish (US)
JournalNature Communications
Issue number1
StatePublished - Jun 6 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): CRF-2015-2646-CRG4
Acknowledgements: The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST) and the KAUST Office of Sponsored Research (OSR) under Award No. CRF-2015-2646-CRG4. We would like to thank Matthijs van Waveren, Antonio M. Arena and Alain Clo of KAUST IT Research Computing and Amine El Helou of MathWorks Ltd for their precious help in speeding up the MATLAB analysis and for providing the KAUST high performance computing (HPC) Add-on for the direct submission of the MATLAB script to the KAUST Noor computer clusters. We thank Virginia Unkefer and Lina Mynar for editing the manuscript.


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