Department of Chemistry and Chemical Biology, TU Dortmund University , D-44221 Dortmund, Germany.
Helmholtz-Zentrum Berlin, D-14109 Berlin, Germany.
Langmuir. 2017 Apr 25;33(16):3982-3990. doi: 10.1021/acs.langmuir.7b00651. Epub 2017 Apr 12.
We have studied the formation and functional properties of polyelectrolyte multilayers where calmodulin (CaM) is used as a polyanion. CaM is known to populate distinct conformational states upon binding Ca and small ligand molecules. Therefore, we have also probed the effects of Ca ions and trifluoperazine (TFP) as ligand molecule on the interfacial structures. Multilayers with the maximum sequence PEI-(PSS-PAH)-CaM-PAH-CaM-PAH have been deposited on silicon wafers and characterized by X-ray and neutron reflectometry. From the analysis of all data, several remarkable conclusions can be drawn. When CaM is deposited for the second time, a much thicker sublayer is produced than in the first CaM deposition step. However, upon rinsing with PAH, very thin CaM-PAH sublayers remain. There are no indications that ligand TFP can be involved in the multilayer buildup due to strong CaM-PAH interactions. However, there is a significant increase in the multilayer thickness upon removal of Ca ions from holo-CaM and an equivalent decrease in the multilayer thickness upon subsequent saturation of apo-CaM with Ca ions. Presumably, CaM can still be toggled between an apo and a holo state, when it is embedded in polyelectrolyte multilayers, providing an approach to design bioresponsive interfaces.
我们研究了聚电解质多层的形成和功能特性，其中钙调蛋白 (CaM) 被用作聚阴离子。已知 CaM 在结合 Ca 和小分子配体分子时会呈现出不同的构象状态。因此，我们还研究了 Ca 离子和三氟拉嗪 (TFP) 作为配体分子对界面结构的影响。在硅晶片上沉积了具有最大序列 PEI-(PSS-PAH)-CaM-PAH-CaM-PAH 的多层，并通过 X 射线和中子反射法进行了表征。从所有数据的分析中，可以得出几个显著的结论。当第二次沉积 CaM 时，生成的亚层比第一次 CaM 沉积步骤厚得多。然而，在用 PAH 冲洗后，仍保留非常薄的 CaM-PAH 亚层。没有迹象表明配体 TFP 可以由于强 CaM-PAH 相互作用而参与多层的构建。然而，当从全钙调蛋白中去除 Ca 离子时，多层厚度会显著增加，而当随后用 Ca 离子饱和脱钙钙调蛋白时，多层厚度会相应减少。推测当 CaM 嵌入聚电解质多层时，它仍然可以在 apo 和 holo 状态之间切换，为设计生物响应性界面提供了一种方法。
