Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, Madrid 28040, Spain.
J Am Chem Soc. 2012 May 16;134(19):8010-3. doi: 10.1021/ja301092z. Epub 2012 May 7.
Conformational switches are macromolecules that toggle between two states (active/inactive or folded/unfolded) upon specific binding to a target molecule. These molecular devices provide an excellent scaffold for developing real-time biosensors. Here we take this concept one step beyond to build high-performance conformational rheostat sensors. The rationale is to develop sensors with expanded dynamic range and faster response time by coupling a given signal to the continuous (rather than binary) unfolding process of one-state downhill folding protein modules. As proof of concept we investigate the pH and ionic-strength sensing capabilities of the small α-helical protein BBL. Our results reveal that such a pH/ionic-strength sensor exhibits a linear response over 4 orders of magnitude in analyte concentration, compared to the 2 orders of magnitude for switches, and nearly concentration-independent microsecond response times.
构象开关是指在与靶分子特异性结合后，能够在两种状态（活性/非活性或折叠/未折叠）之间切换的大分子。这些分子器件为开发实时生物传感器提供了极好的支架。在这里，我们将这一概念进一步拓展，构建了高性能构象变阻器传感器。其基本原理是通过将给定信号与单一状态下坡折叠蛋白模块的连续（而非二进制）展开过程相结合，开发出具有更大动态范围和更快响应时间的传感器。作为概念验证，我们研究了小α螺旋蛋白 BBL 的 pH 值和离子强度感应能力。我们的结果表明，与开关的 2 个数量级相比，这种 pH/离子强度传感器在分析物浓度上具有超过 4 个数量级的线性响应，并且响应时间几乎与浓度无关，为微秒级。
