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arXiv 1402.0385q-bio.BM
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有效势的迭代推导在原子尺度上对蛋白质构象空间进行采样

Iterative derivation of effective potentials to sample the conformational space of proteins at atomistic scale

R. Capelli, C. Paissoni, P. Sormanni, G. Tiana

摘要:

目前的计算机能力使得有可能进行模拟的小型系统与便携式,明确的溶剂潜力,实现高度的准确性。然而,必须采用简化的模型来利用大型系统的行为或对较小系统进行系统扫描。虽然强大的算法是可用的,以方便采样的构象空间,成功的应用程序,这样的模型受到阻碍的可用性足够简单的潜力,能够令人满意地再现已知的系统属性。我们开发了一个原子间的潜力,以计算经济的方式来考虑蛋白质的一些属性。在全原子、隐式溶剂模型中,通过不同原子类型之间的接触函数来定义电势。相关的数值可以优化的迭代蒙特卡罗方案上的任何可用的实验数据,只要它们是表达为热平均的一些构象特性。我们在三种不同的蛋白质上测试这个模型,我们还使用显式构象采样对所有可能的点突变进行扫描。由此产生的模型,优化仅在一个子集的原生距离,不仅重现本地构象在几个Angstrom从实验的,但显示本地和变性状态之间的合作过渡,并正确地预测测得的自由能变化与点突变。此外,与其他基于结构的模型不同,我们的方法留下了残余程度的挫折,这是已知的蛋白质分子中存在的。

英文摘要:

The current capacity of computers makes it possible to perform simulations of small systems with portable, explicit-solvent potentials achieving high degree of accuracy. However, simplified models must be employed to exploit the behaviour of large systems or to perform systematic scans of smaller systems. While powerful algorithms are available to facilitate the sampling of the conformational space, successful applications of such models are hindered by the availability of simple enough potentials able to satisfactorily reproduce known properties of the system. We develop an interatomic potential to account for a number of properties of proteins in a computationally economic way. The potential is defined within an all-atom, implicit solvent model by contact functions between the different atom types. The associated numerical values can be optimised by an iterative Monte Carlo scheme on any available experimental data, provided that they are expressible as thermal averages of some conformational properties. We test this model on three different proteins, for which we also perform a scan of all possible point mutations with explicit conformational sampling. The resulting models, optimised solely on a subset of native distances, not only reproduce the native conformations within a few Angstroms from the experimental ones, but show the cooperative transition between native and denatured state and correctly predict the measured free--energy changes associated with point mutations. Moreover, differently from other structure-based models, our method leaves a residual degree of frustration, which is known to be present in protein molecules.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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