Manipulating protein conformations by single-molecule AFM-FRET nanoscopy

ACS Nano. 2012 Feb 28;6(2):1221-9. doi: 10.1021/nn2038669. Epub 2012 Feb 1.

Abstract

Combining atomic force microscopy and fluorescence resonance energy transfer spectroscopy (AFM-FRET), we have developed a single-molecule AFM-FRET nanoscopy approach capable of effectively pinpointing and mechanically manipulating a targeted dye-labeled single protein in a large sampling area and simultaneously monitoring the conformational changes of the targeted protein by recording single-molecule FRET time trajectories. We have further demonstrated an application of using this nanoscopy on manipulation of single-molecule protein conformation and simultaneous single-molecule FRET measurement of a Cy3-Cy5-labeled kinase enzyme, HPPK (6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase). By analyzing time-resolved FRET trajectories and correlated AFM force pulling curves of the targeted single-molecule enzyme, we are able to observe the protein conformational changes of a specific coordination by AFM mechanic force pulling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Diphosphotransferases / chemistry*
  • Fluorescence Resonance Energy Transfer / methods*
  • Glass / chemistry
  • Mechanical Phenomena
  • Microscopy / methods*
  • Microscopy, Atomic Force / methods*
  • Models, Molecular
  • Nanotechnology / methods*
  • Protein Conformation

Substances

  • Diphosphotransferases
  • 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine pyrophosphokinase