摘要
Receptor-ligand bond dissociation under applied force is crucial to elucidate its biological functionality when the molecular bond is usually connected to a mechanical probe. While the impact of probe stiffness, k, on bond rupture force has recently at- tracted more and more attention, the mechanism of how it affects the bond lifetime, however, remains unclear. Here we quanti- fied the dissociation lifetime of selectin-ligand bond using an optical trap assay with low stiffness ranging from 3.5×10^-3 to 4.7×10^-2 pN/nm. Our results indicated that bond lifetime yielded distinct distributions with different probe stiffness, implying the stochastic feature of bond dissociation. It was also found that the mean lifetime varied with probe stiffness and that the catch bond nature was visualized at k≥3.0×10^-2 pN/nm. This work furthered the understanding of the forced dissociation of se- lectin-ligand bond at varied probe stiffness, which is physiologically relevant to the tethered rolling of leukoeytes under blood flow.
Receptor-ligand bond dissociation under applied force is crucial to elucidate its biological functionality when the molecular bond is usually connected to a mechanical probe. While the impact of probe stiffness, k, on bond rupture force has recently attracted more and more attention, the mechanism of how it affects the bond lifetime, however, remains unclear. Here we quantified the dissociation lifetime of selectin-ligand bond using an optical trap assay with low stiffness ranging from 3.5×10-3 to 4.7×10-2 pN/nm. Our results indicated that bond lifetime yielded distinct distributions with different probe stiffness, implying the stochastic feature of bond dissociation. It was also found that the mean lifetime varied with probe stiffness and that the catch bond nature was visualized at k■3.0×10-2 pN/nm. This work furthered the understanding of the forced dissociation of selectin-ligand bond at varied probe stiffness, which is physiologically relevant to the tethered rolling of leukocytes under blood flow.
基金
supported by the National Natural Science Foundation of China (Grant Nos. 10902117, 10702075, 30730032 and 11072251)
Chinese Academy of Sciences (Grant Nos. KJCX2-YW-L08 and Y2010030)
the National Key Basic Research Foundation of China (Grant No. 2011CB710904)
Dr. MCEVER Rodger P. (Oklahoma Medical Research Foundation) for generous gifts of P-selectin, S12, G1, PL2, and PL1 proteins
