Effects of excluded surface area and adsorbate clustering on surface adsorption of proteins. II. Kinetic models
Effects of excluded surface area and adsorbate clustering on surface adsorption of proteins. II. Kinetic models
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DOI：
10.1016/s0006-3495(01)76136-x
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发表时间：
2001-04-01
影响因子：
3.4
通讯作者：
Minton, AP
中科院分区：
文献类型：
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作者：
Minton, AP
最近提出了蛋白质的平衡表面吸附模型（Minton，A.P.，2000.Biophys.Chem.86：239-247），其中由于吸附物分子的区域排斥而产生的负协同性通过形成吸附蛋白质分子的单层表面簇的异质群体而在不同程度上得到补偿。在目前的工作中，这一概念被扩展到处理蛋白质吸附动力学。据推测，簇可能通过两种不同的动力学途径生长。第一条途径是吸附的单体扩散到预先存在的簇的边缘并随后吸积。第二条途径包括将溶液中的单体直接沉积到预先存在的簇的上（面向溶液）表面（“背负式”沉积），然后并入簇中。针对两种不同的簇结构和能量学极限模型进行的吸附时间过程的计算结果表明，在没有背负式沉积的情况下，吸附质形成簇的趋势的增强可以减少但不能消除由于吸附质的表面积排斥而导致的负动力学协同性，显然，非合作（朗缪尔式）和正合作吸附进度曲线在质量上与几项已发表的实验研究中报告的曲线类似，需要通过背负式沉积途径的总吸附通量的很大一部分。根据本文和上述参考文献中开发的模型，表面簇的形成应该是蛋白质非位点特异性表面吸附的常见伴随物，并且可能为体内有组织的“蛋白质机器”的组装提供重要机制。
Models for equilibrium surface adsorption of proteins have been recently proposed (Minton, A. P., 2000. Biophys. Chem. 86:239-247) in which negative cooperativity due to area exclusion by adsorbate molecules is compensated to a variable extent by the formation of a heterogeneous population of monolayer surface clusters of adsorbed protein molecules. In the present work this concept is extended to treat the kinetics of protein adsorption. It is postulated that clusters may grow via two distinct kinetic pathways. The first pathway is the diffusion of adsorbed monomer to the edge of a preexisting cluster and subsequent accretion. The second pathway consists of direct deposition of a monomer in solution onto the upper (solution-facing) surface of a preexisting cluster ("piggyback" deposition) and subsequent incorporation into the cluster, Results of calculations of the time course of adsorption, carried out for two different limiting models of cluster structure and energetics, shaw that in the absence of piggyback deposition, enhancement of the tendency of adsorbate to cluster can reduce, but not eliminate, the negative kinetic cooperativity due to surface area exclusion by adsorbate, Apparently noncooperative (Langmuir-like) and positively cooperative adsorption progress curves, qualitatively similar to those reported in several published experimental studies, require a significant fraction of total adsorption flux through the piggyback deposition pathway. According to the model developed here and in the above-mentioned reference, the formation of surface clusters should be a common concomitant of non-site-specific surface adsorption of proteins, and may provide an important mechanism for assembly of organized "protein machines" in vivo.