Open-ITC: an alternate computational approach to analyze the isothermal titration calorimetry data of complex binding mechanisms
Open-ITC: an alternate computational approach to analyze the isothermal titration calorimetry data of complex binding mechanisms
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DOI：
10.1002/jmr.1154
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发表时间：
2011-11-01
影响因子：
2.7
通讯作者：
Mohanty, Smita
中科院分区：
文献类型：
--
作者：
Krishnamoorthy, Janarthanan;Mohanty, Smita
等温滴定量热法（ITC）是通过热力学测量定量分析蛋白质-蛋白质或蛋白质-配体相互作用的整体机制的重要技术。在不同的结合机制中，与顺序结合机制相比，平行和配体诱导的蛋白质寡聚机制在技术上难以分析。在这里，我们提出了一种作为“Open-ITC”程序实施的方法，该方法消除了对游离配体浓度 [L] 和结合配体摩尔分数的精确分析表达式的需要。热图分析所需的。采用基于遗传算法的优化确定热力学参数，并通过计算雅可比矩阵评估其标准误差在全局最小值处。这种方法对于单位点和双位点结合蛋白-配体系统产生了统计上一致的结果。此外，两步顺序、平行和配体诱导寡聚模型的比较模拟表明，只有当第一个结合步骤比第二个结合步骤弱时，它们的机制差异才能在 ITC 热分析图中辨别出来（K(1)
Isothermal titration calorimetry (ITC) is an important technique used in quantitatively analyzing the global mechanism of protein-protein or protein-ligand interactions through thermodynamic measurements. Among different binding mechanisms, the parallel and ligand induced protein oligomerization mechanisms are technically difficult to analyze compared with a sequential binding mechanism. Here, we present a methodology implemented as a program "Open-ITC" that eliminates the need for exact analytical expressions for free ligand concentrations [ L] and mole fractions of bound ligand. that are required for the thermogram analysis. Adopting a genetic algorithm-based optimization, the thermodynamic parameters are determined, and its standard error is evaluated at the global minimum by calculating the Jacobian matrix. This approach yielded a statistically consistent result for a single-site and a two-site binding protein-ligand system. Further, a comparative simulation of a two-step sequential, a parallel, and a ligand induced oligomerization model revealed that their mechanistic differences are discernable in ITC thermograms, only if the first binding step is weaker compared with the second binding step (K(1)