摘要(英) |
="" we="" present="" a="" theoretical="" model="" to="" study="" the="" lifetime="" t(nt,="" f)="" of="" an="" adhesion
="" cluster="" under="" external="" force="" f,="" where="" nt="" is="" size="" and="" f="F/Nt." the
="" composed="" parallel="" ligand-receptor="" pairs.="" find="" character-
="" istic="" fc="" predicted="" by="" rate="" equation.="" monte="" carlo="" simulation,="" we
="" show="" (i)="" when=""> fc, T is independent of Nt. This can be explained by the
rate equation which predicts that the fraction of connected ligand-receptor
pairs nb(t) depends on f, but not on Nt. (ii)When f = fc, lnT(Nt, f) ∼ lnNt.
To explain the result we construct the effective free energy G and treat the
force pulling process as a particle moving under G in Nb space. G(f = fc)
has a flat region where the particle spends most of its lifetime to cross it.
By estimating the width of the flat region with dimensional analysis, we find
lnT(Nt, f) ∼ lnNt. (iii) When f < fc regime, lnT(Nt, f) ∼ Nt because
G(f < fc) has a barrier with barrier height ∼ Nt and lifetime T comes from
the barrier crossing time of the particle, as a result lnT(Nt, f) ∼ Nt. Finally
we show that the above three relations exist as long as the rebinding and
unbinding rates are functions of f and nb. |
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