Strength of ligand-receptor cluster under external force : deterministic model

• Main Authors: Yi-Ping Chu, 朱怡苹
• Other Authors: Hsuan-Yi Chen
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/86737210414127701314

碩士 === 國立中央大學 === 生物物理研究所 === 95 === We present a theoretical model that describes ligand-receptor cluster under external force. We modify the model of Bell [1] by considering the rebinding of broken bonds in a consistent way. The stability of the cluster is studied by the rate equation of Nb, the number of connected bonds. Our study reveals that for a cluster with N parallel bonds under external force F, the lifetime of the cluster depends only on the force acting on each bond f = F/N. There exists a critical force Fc = Nfc below which the cluster is stable and above which the cluster dissociates. When f = fc, the number of rupture events per unit time is equal to that of rebinding at Nb^* = Nnb^*. We find nb^*~1, i.e., the effect of rebinding is important when most of the bonds are connected. When f approaches fc from above, the cluster spends most of the time near nb^*, the true lifetime of the cluster is shorter than Bell’s prediction and has a power law behavior T ~(f − fc)^(−1/2). We also show that the true lifetime of the cluster is longer than Bell’s prediction when f is significantly greater than fc due to different number of connected bonds predicted by both theories in the absence of force. When f =fc, for a finite size cluster, the bond number fluctuation is important, the lifetime of the cluster is related to the cluster size by T ~N^(1/3).