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Nano Lett. 2016 Mar 9;16(3):2096-102. doi: 10.1021/acs.nanolett.6b00305. Epub 2016 Feb 3.

Spider Silk Peptide Is a Compact, Linear Nanospring Ideal for Intracellular Tension Sensing.

Author information

1
Cardiovascular Research Center, University of Virginia , Charlottesville, Virginia 22908, United States.
2
Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California , Irvine, California 92697, United States.
3
Yale Cardiovascular Research Center, Departments of Internal Medicine (Section of Cardiovascular Medicine) and Cell Biology, Yale University , New Haven, Connecticut 06511, United States.
4
Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
5
Department of Biophysics & Biophysical Chemistry, Department of Biophysics, and Department of Biomedical Engineering, Johns Hopkins University , Baltimore, Maryland 21205, United States.
6
Howard Hughes Medical Institute , Baltimore, Maryland 21205, United States.

Abstract

Recent development and applications of calibrated, fluorescence resonance energy transfer (FRET)-based tension sensors have led to a new understanding of single molecule mechanotransduction in a number of biological systems. To expand the range of accessible forces, we systematically measured FRET versus force trajectories for 25, 40, and 50 amino acid peptide repeats derived from spider silk. Single molecule fluorescence-force spectroscopy showed that the peptides behaved as linear springs instead of the nonlinear behavior expected for a disordered polymer. Our data are consistent with a compact, rodlike structure that measures 0.26 nm per 5 amino acid repeat that can stretch by 500% while maintaining linearity, suggesting that the remarkable elasticity of spider silk proteins may in part derive from the properties of individual chains. We found the shortest peptide to have the widest range of force sensitivity: between 2 pN and 11 pN. Live cell imaging of the three tension sensor constructs inserted into vinculin showed similar force values around 2.4 pN. We also provide a lookup table for force versus intracellular FRET for all three constructs.

KEYWORDS:

FLIM; Force-sensor; force-fluorescence spectroscopy; optical tweezers; single-molecule FRET; spider flagelliform silk

PMID:
26824190
PMCID:
PMC4851340
DOI:
10.1021/acs.nanolett.6b00305
[Indexed for MEDLINE]
Free PMC Article

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