Department of Physics, Jagiellonian University, 30-059 Cracow, Poland.
J Mol Recognit. 2011 Jul-Aug;24(4):715-23. doi: 10.1002/jmr.1108.
Integrins require the divalent ions magnesium and manganese for ligand recognition. Here we mechanically enforced bond dissociation to explore the influence of these ions on the mechanical strength of the specific bond between α(7) β(1) integrin and its pathologically relevant ligand invasin. Upon addition of these cations to the measurement buffer, we observe a pronounced increase in the force necessary to separate integrin and invasin coated beads. Both ions were found to work synergistically. With free invasin in the measurement buffer we furthermore observe that competitive blocking of binding sites overrides the increase in binding strength of individual beads. We show that this is due to a very strong dependence of bond affinity on divalent ions. Our study illustrates the importance of divalent ions for the regulation of force transmission by integrin ligand bonds on the molecular level.
整合素需要二价离子镁和锰来识别配体。在这里，我们通过机械强制键解离来探索这些离子对α(7)β(1)整合素与其病理相关配体入侵素之间特定键的机械强度的影响。在向测量缓冲液中添加这些阳离子后，我们观察到分离整合素和入侵素包被珠所需的力显著增加。两种离子都被发现具有协同作用。在测量缓冲液中有游离入侵素的情况下，我们还观察到，结合位点的竞争性阻断会超过单个珠结合强度的增加。我们表明，这是由于键亲和力对二价离子非常强的依赖性。我们的研究说明了二价离子对于整合素配体键在分子水平上传递力的调节的重要性。
