Hoffmann Silke, Funke Susanne Aileen, Wiesehan Katja, Moedder Susanne, Glück Julian Marius, Feuerstein Sophie, Gerdts Matthias, Mötter Jessica, Willbold Dieter
ISB-3, Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
Mol Biosyst. 2010 Jan;6(1):126-33. doi: 10.1039/b910945e. Epub 2009 Sep 21.
Protein-ligand interactions characterise and govern the current state and fate of a living cell. The specificity of proteins is mainly determined by the relative affinities to each potential ligand. To investigate the consequences and potentials of ligands with increased specificity in comparison with ligands optimised solely for affinity, it was necessary to identify ligands that are optimised towards specificity instead of a barely optimised affinity to a given target. In the presented example, a modified phage display screening procedure yielded specific ligands for the LckSH3 domain. We found that increased specificity of one of the hereby obtained ligands for LckSH3 is achieved at the cost of a slightly reduced affinity to LckSH3 and a drastically reduced affinity to other SH3 domains. A surface plasmon resonance experiment simulating in vivo-like realistic competitive binding conditions exerted enhanced binding behaviour of the specific ligand under these binding conditions. The experimental data, together with a mathematical model describing the complex experimental situation, and theoretical considerations lead to the conclusion that increased specificity is achieved at the cost of reduced affinity, but after all, it pays if the ligand is applied under realistic, i.e. competitive, conditions.
蛋白质-配体相互作用表征并决定了活细胞的当前状态和命运。蛋白质的特异性主要由其对每种潜在配体的相对亲和力决定。为了研究与仅针对亲和力进行优化的配体相比，具有更高特异性的配体的后果和潜力，有必要鉴定针对特异性而非对给定靶标的勉强优化的亲和力进行优化的配体。在给出的示例中，一种改良的噬菌体展示筛选程序产生了针对LckSH3结构域的特异性配体。我们发现，在此获得的一种针对LckSH3的配体的特异性提高是以对LckSH3的亲和力略有降低以及对其他SH3结构域的亲和力大幅降低为代价的。在模拟体内真实竞争结合条件的表面等离子体共振实验中，该特异性配体在这些结合条件下表现出增强的结合行为。实验数据，连同描述复杂实验情况的数学模型以及理论考量，得出结论：特异性的提高是以亲和力降低为代价的，但毕竟，如果在真实的即竞争的条件下应用该配体，那么这是值得的。
