Single-molecule diffusion and conformational dynamics by spatial integration of temporal fluctuations

Abstract
Single-molecule localization and tracking has been used to translate spatiotemporal information of individual molecules to map their diffusion behaviours. However, accurate analysis of diffusion behaviours and including other parameters, such as the conformation and size of molecules, remain as limitations to the method. Here, we report a method that addresses the limitations of existing single-molecular localization methods. The method is based on temporal tracking of the cumulative area occupied by molecules. These temporal fluctuations are tied to molecular size, rates of diffusion and conformational changes. By analysing fluorescent nanospheres and double-stranded DNA molecules of different lengths and topological forms, we demonstrate that our cumulative-area method surpasses the conventional single-molecule localization method in terms of the accuracy of determined diffusion coefficients. Furthermore, the cumulative-area method provides conformational relaxation times of structurally flexible chains along with diffusion coefficients, which together are relevant to work in a wide spectrum of scientific fields.

Citation
Serag, M. F. et al. Single-molecule diffusion and conformational dynamics by spatial integration of temporal fluctuations. Nat. Commun. 5:5123 doi: 10.1038/ncomms6123 (2014).

Publisher
Springer Nature

Journal
Nature Communications

DOI
10.1038/ncomms6123

PubMed ID
25283876

PubMed Central ID
PMC4205855

Additional Links
http://www.nature.com/doifinder/10.1038/ncomms6123

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