Mode of heavy meromyosin adsorption and motor function correlated with surface hydrophobicity and charge
Mode of heavy meromyosin adsorption and motor function correlated with surface hydrophobicity and charge
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DOI：
10.1021/la7008682
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发表时间：
2007-10-23
期刊：
影响因子：
3.9
通讯作者：
Nicholls, Ian A.
中科院分区：
文献类型：
--
作者：
Albet-Torres, Nuria;O'Mahony, John;Nicholls, Ian A.
在体外运动分析是有价值的肌动球蛋白功能的基础研究，最近已结合纳米结构技术的纳米技术应用的发展。然而，肌球蛋白马达片段（重肌球蛋白，HMM）和人工表面之间的相互作用机制的了解有限，阻碍了基础研究的发展和解释。在这里，我们阐明了HMM表面相互作用机制的范围内带负电荷的表面（硅烷化玻璃和二氧化硅），这是相关的纳米技术和基础研究。结果表明，HMM推进的肌动蛋白丝滑动速度（在单次注射HMM后，120 μ g/mL）随着表面的接触角（在20-80度的范围内）而增加。然而，石英晶体微天平（QCM）的研究表明，在这些条件下的HMM（与耦合水）的吸附减少。该结果和肌动蛋白丝结合数据，连同先前的HMM密度测量（Sundberg，M.; Balaz，M.; Bunk，R.; Rosengren-Holmberg，J. P.; Montelius，L.;尼科尔斯岛一、Omling，P.; Tagerud，S.; Mansson，A. Langmuir 2006，22，7302-7312。Balaz，M.; Sundberg，M.; Mr. P.; Kvassman，J.; Mansson，A. Biochemistry 2007，46，7233-7251）与（1）HMM单层和（2）在不同表面接触角下的不同HMM构型一致。更具体地，QCM和体外运动性测定数据与其中分子通过其柔性C-末端尾部（HMMC）或通过其带正电荷的N-末端马达结构域（HMMN）吸附而没有其他表面接触点的模型一致。zeta电位的测量表明，接触角的增加与表面的负电荷减少相关。因此，HMMC构型在高接触角下将是主要构型，但在低接触角下将补充有静电吸附的HMM分子（HMMN构型）。这将解释在后一种条件下较高的初始HMM吸附（从概率参数）。此外，因为HMMN模式将没有肌动蛋白结合，所以它也将解释在低接触角下较低的滑动速度。结果进行了比较，以前的研究微管驱动蛋白系统，并讨论了有关肌动球蛋白和纳米技术的发展和应用的基础研究。
The in vitro motility assay is valuable for fundamental studies of actomyosin function and has recently been combined with nanostructuring techniques for the development of nanotechnological applications. However, the limited understanding of the interaction mechanisms between myosin motor fragments (heavy meromyosin, HMM) and artificial surfaces hampers the development as well as the interpretation of fundamental studies. Here we elucidate the HMM-surface interaction mechanisms for a range of negatively charged surfaces (silanized glass and SiO2), which is relevant both to nanotechnology and fundamental studies. The results show that the HMM-propelled actin filament sliding speed (after a single injection of HMM, 120 mu g/mL)increased with the contact angle of the surfaces (in the range of 20-80 degrees). However, quartz crystal microbalance (QCM) studies suggested a reduction in the adsorption of HMM (with coupled water) under these conditions. This result and actin filament binding data, together with previous measurements of the HMM density (Sundberg, M.; Balaz, M.; Bunk, R.; Rosengren-Holmberg, J. P.; Montelius, L.; Nicholls, I. A.; Omling, P.; Tagerud, S.; Mansson, A. Langmuir 2006, 22, 7302-7312. Balaz, M.; Sundberg, M.; Persson, M.; Kvassman, J.; Mansson, A. Biochemistry 2007, 46, 7233-7251), are consistent with (1) an HMM monolayer and (2) different HMM configurations at different contact angles of the surface. More specifically, the QCM and in vitro motility assay data are consistent with a model where the molecules are adsorbed either via their flexible C-terminal tail part (HMMC) or via their positively charged N-terminal motor domain (HMMN) without other surface contact points. Measurements of zeta potentials suggest that an increased contact angle is correlated with a reduced negative charge of the surfaces. As a consequence, the HMMC configuration would be the dominant configuration at high contact angles but would be supplemented with electrostatically adsorbed HMM molecules (HMMN configuration) at low contact angles. This would explain the higher initial HMM adsorption (from probability arguments) under the latter conditions. Furthermore, because the HMMN mode would have no actin binding it would also account for the lower sliding velocity at low contact angles. The results are compared to previous studies of the microtubule-kinesin system and are also discussed in relation to fundamental studies of actomyosin and nanotechnological developments and applications.