Raffaini Giuseppina, Ganazzoli Fabio
Dipartimento di Chimica, Materiali e Ingegneria Chimica "G Natta", Sez Chimica, Politecnico di Milano, 20131 Milano, Italy.
Langmuir. 2004 Apr 13;20(8):3371-8. doi: 10.1021/la0357716.
We report atomistic simulations of the adsorption of a fibronectin type I module on a hydrophobic graphite surface. This module comprises only beta-sheets, unlike the albumin fragments previously investigated by us which contained only alpha-helices (Raffaini, G.; Ganazzoli, F. Langmuir 2003, 19, 3403-3412). As done in the latter case, most simulations are carried out in an effective dielectric medium by energy minimizations and molecular dynamics (MD). Further optimizations and MD runs in the explicit presence of water are also performed to assess the stability of the geometries found and to describe the solvation of the adsorbed fibronectin module. The initial adsorption is accompanied by local rearrangements of the strands in contact with the surface, but the overall molecular structure is largely preserved. Much larger rearrangements take place at longer times as found through the MD runs, with the molecule spreading as much as possible so as to maximize the surface coverage, hence the interaction energy, despite a significant strain energy. Energetic aspects of adsorption together with the concomitant size change are discussed in comparison with our previous results for two albumin fragments.
我们报告了纤连蛋白I型模块在疏水石墨表面吸附的原子模拟。与我们之前研究的仅包含α-螺旋的白蛋白片段不同，该模块仅由β-折叠组成（拉法伊尼，G.；加纳佐利，F.《朗缪尔》2003年，第19卷，3403 - 3412页）。与后一种情况一样，大多数模拟是在有效的介电介质中通过能量最小化和分子动力学（MD）进行的。还在明确存在水的情况下进行了进一步的优化和MD运行，以评估所发现几何结构的稳定性，并描述吸附的纤连蛋白模块的溶剂化情况。初始吸附伴随着与表面接触的链的局部重排，但整体分子结构基本保持不变。通过MD运行发现，在更长时间内会发生更大的重排，分子会尽可能地展开以最大化表面覆盖率，从而最大化相互作用能，尽管存在显著的应变能。与我们之前关于两个白蛋白片段的结果相比，讨论了吸附的能量方面以及伴随的尺寸变化。
