Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
Langmuir. 2010 Jul 20;26(14):11951-7. doi: 10.1021/la101269q.
The detection probability of rupture events in AFM force spectroscopy measurements presents a viable alternative to standard methods for extracting kinetic parameters of dissociation. The detection probability has a maximum as a function of the probe velocity where (1) the probability to form a molecular bond is independent of the probe velocity and (2) the detection of rupture events is limited by noise and performed with a constant density of data points per distance of the probe displacement. This newly developed model indicates that the optimal detection velocity is independent of dissociation rate and depends on the distance to the barrier kinetic parameter. Therefore, the kinetic parameters of bond dissociation can be extracted from the dependence of detection probability on probe velocity and the detection threshold. This approach is sensitive to low rupture forces and therefore is complementary to the common most probable force data analysis approach. The developed approach is tested using rupture forces measured with specific bonds between biotin and streptavidin and with nonspecific bonds between linear alkanes in water. Results for the analysis of specific bonds rupture are consistent with the previous measurements, suggesting that rupture forces spanning a wide range of values originate from the same binding potential. Kinetic parameters obtained for linear alkanes are significantly different from previous measurements suggesting possible heterogeneity of the bound state.
在原子力显微镜（AFM）力谱测量中，断裂事件的检测概率为提取离解动力学参数提供了一种可行的替代标准方法。检测概率作为探针速度的函数具有最大值，其中：（1）形成分子键的概率与探针速度无关；（2）断裂事件的检测受到噪声限制，并且以探针位移距离的固定数据点密度进行。这个新开发的模型表明，最佳检测速度与离解速率无关，而是取决于到势垒动力学参数的距离。因此，可以从检测概率对探针速度和检测阈值的依赖性中提取键离解的动力学参数。该方法对低断裂力敏感，因此与常见的最可能力数据分析方法互补。该方法使用生物素和链霉亲和素之间的特定键以及水中线性烷烃之间的非特异性键测量的断裂力进行了测试。分析特定键断裂的结果与先前的测量结果一致，表明跨越广泛值范围的断裂力源自相同的结合势。对于线性烷烃获得的动力学参数与先前的测量值显著不同，表明结合状态可能存在异质性。
