PLoS ONE (Jan 2017)

Multispot single-molecule FRET: High-throughput analysis of freely diffusing molecules.

  • Antonino Ingargiola,
  • Eitan Lerner,
  • SangYoon Chung,
  • Francesco Panzeri,
  • Angelo Gulinatti,
  • Ivan Rech,
  • Massimo Ghioni,
  • Shimon Weiss,
  • Xavier Michalet

DOI
https://doi.org/10.1371/journal.pone.0175766
Journal volume & issue
Vol. 12, no. 4
p. e0175766

Abstract

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We describe an 8-spot confocal setup for high-throughput smFRET assays and illustrate its performance with two characteristic experiments. First, measurements on a series of freely diffusing doubly-labeled dsDNA samples allow us to demonstrate that data acquired in multiple spots in parallel can be properly corrected and result in measured sample characteristics consistent with those obtained with a standard single-spot setup. We then take advantage of the higher throughput provided by parallel acquisition to address an outstanding question about the kinetics of the initial steps of bacterial RNA transcription. Our real-time kinetic analysis of promoter escape by bacterial RNA polymerase confirms results obtained by a more indirect route, shedding additional light on the initial steps of transcription. Finally, we discuss the advantages of our multispot setup, while pointing potential limitations of the current single laser excitation design, as well as analysis challenges and their solutions.