TABLE 1

Comparison of molecular-force sensorsa

Type and sensorSpectroscopic rulerLinkerMax S/BbForce dynamic range (pN)Protein(s) targetedReference(s)
GETS
    stFRETFRETα-Helical peptide1.8-fold∼5–7cSpectrin, α-actinin, filamin A, collagen-19103, 104
    sstFRETFRETSpectrin repeat2-fold∼5–7cα-Actinin105107
    cpstFRETFRETPoly(G) peptide4-fold∼5–10cSpectrin108
    PriSSMPRIMAS(GGS)92-foldNDMyosin II109, 111
    TSModFRET(GPGGA)81.3-fold∼1–6cVinculin, E-cadherin, VE-cadherin, PECAM, β-spectrin, MUC135, 98, 112116
Immobilized
    MTFM-FRETFRETPEG2410-fold∼1–20dEGFR, integrins99, 117
    MTFM-NSETNSETPEG8010-fold∼1–25dIntegrins126, 127
    MTFM-DNAFRETDNA hairpin30-fold∼5–16cIntegrins129
    TPFRETDNA hairpin∼30-fold∼6–17cIntegrins130
    MTSFRET(GPGGA)83-fold∼1–7dIntegrins118, 135
    TGTNADNANA∼12–56dIntegrins, Notch/Delta131
  • a ND, not determined; NA, not applicable.

  • b Maximum signal/background ratio (S/B) is defined as (1 − ETFmax)/(1 − ETF = 0), where ETFmax is the energy transfer efficiency at full linker extension and ETF = 0 is the energy transfer efficiency in the absence of force.

  • c The sensor response was experimentally calibrated.

  • d Sensor response was determined through calculation.