Dynamic force spectroscopy on a single antibody-antigen bond at gives the most…

PHYSICS · Multi-part · Fermi University Physics · Biophysics & Medical Physics · Macromolecules, membranes and cell architecture · Molecular machines, transport and bioenergetics

Forces, Machines and Signals, Ch Measuring one molecule: traps, tweezers and single-molecule fluorescence

Problem

Dynamic force spectroscopy on a single antibody-antigen bond at 298 K298\,\mathrm{K} gives the most probable rupture force f∗=45 pNf^* = 45\,\mathrm{pN} at a loading rate r=100 pN s−1r = 100\,\mathrm{pN\,s^{-1}}, and f∗=75 pNf^* = 75\,\mathrm{pN} at r=1.0×105 pN s−1r = 1.0\times10^5\,\mathrm{pN\,s^{-1}}. ((a)) Find the slope of f∗f^* against ln⁡r\ln r implied by these two points. ((b)) Use the Bell-Evans result f∗=(kBT/x‡)ln⁡(rx‡/k0kBT)f^* = (k_BT/x^\ddagger)\ln(rx^\ddagger/k_0k_BT) to extract the barrier distance x‡x^\ddagger.

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