On the Signaling of Electrochemical Aptamer-Based Sensors: Collision- and Folding-Based Mechanisms.
On the Signaling of Electrochemical Aptamer-Based Sensors: Collision- and Folding-Based Mechanisms.
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DOI：
10.1002/elan.200804564
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发表时间：
2009-06-01
期刊：
影响因子：
3
通讯作者：
Plaxco, Kevin W.
中科院分区：
文献类型：
--
作者：
Xiao, Yi;Uzawa, Takanori;White, Ryan J.;DeMartini, Daniel;Plaxco, Kevin W.
近年来，出现了一类新型电化学传感器，其基于目标结合诱导的电极结合氧化还原修饰适配体的折叠，并针对从小分子到蛋白质等目标。先前对这些电化学适配体 (E-AB) 传感器的增益和探针密度之间关系的研究表明，信号转导与结合引起的附着氧化还原标签撞击电极的效率变化有关。这反过来表明，如果靶点结合充分改变了适体的灵活性，即使折叠良好的适体也可能支持 E-AB 信号传导。在这里，我们使用凝血酶结合适体对此进行研究，该适体在低离子强度下经历结合诱导的折叠，但即使在不存在其蛋白质靶标的情况下，也可以在较高离子强度下被迫采用折叠构象。我们发现，在凝血酶适体在靶标结合之前完全折叠的条件下，我们仍然获得约。达到饱和目标水平后，E-AB 信号发生 30% 的变化。然而，相比之下，在适体在没有靶标的情况下展开并因此经历结合诱导折叠的条件下，观察到的信号变化是两倍。然而，折叠适体支持 E-AB 信号传导的能力并不普遍：例如，完全折叠的抗 IgE 适体仅产生极小的，约 100 nm。尽管该蛋白质的空间体积较大，但存在目标时信号发生 2.5% 的变化。因此，虽然完全折叠适体中结合诱导的动力学变化似乎可以支持E-AB信号传导，但这种信号传导机制可能不是通用的，并且为了确保高增益传感器的设计，结合必须与大规模构象变化联系起来。
Recent years have seen the emergence of a new class of electrochemical sensors predicated on target binding-induced folding of electrode-bound redox-modified aptamers and directed against targets ranging from small molecules to proteins. Previous studies of the relationship between gain and probe-density for these electrochemical, aptamer-based (E-AB) sensors suggest that signal transduction is linked to binding-induced changes in the efficiency with which the attached redox tag strikes the electrode. This, in turn, suggests that even well folded aptamers may support E-AB signaling if target binding sufficiently alters their flexibility. Here we investigate this using a thrombin-binding aptamer that undergoes binding-induced folding at low ionic strength but can be forced to adopt a folded conformation at higher ionic strength even in the absence of its protein target. We find that, under conditions in which the thrombin aptamer is fully folded prior to target binding, we still obtain a ca. 30% change in E-AB signal upon saturated target levels. In contrast, however, under conditions in which the aptamer is unfolded in the absence of target and thus undergoes binding-induced folding the observed signal change is twice as great. The ability of folded aptamers to support E-AB signaling, however, is not universal: a fully folded anti-IgE aptamer, for example, produces only an extremely small, ca. 2.5% signal change in the presence of target despite the larger steric bulk of this protein. Thus, while it appears that binding-induced changes in the dynamics in fully folded aptamers can support E-AB signaling, this signaling mechanism may not be general, and in order to ensure the design of high-gain sensors binding must be linked to a large-scale conformational change.
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影响因子：
4.9
作者：
Ricci, Francesco;Lai, Rebecca Y.;Plaxco, Kevin W.
通讯作者：
Plaxco, Kevin W.
影响因子：
16.6
作者：
Xiao, Y;Lubin, AA;Plaxco, KW
通讯作者：
Plaxco, KW
影响因子：
14.8
作者：
Xiao, Yi;Lai, Rebecca Y.;Plaxco, Kevin W.
通讯作者：
Plaxco, Kevin W.
影响因子：
3
作者：
Lluis Acero Sanchez, Josep;Baldrich, Eva;O'Sullivan, Ciara K.
通讯作者：
O'Sullivan, Ciara K.
DOI：
10.1021/la800801v
发表时间：
2008-09-16
期刊：
Langmuir : the ACS journal of surfaces and colloids
影响因子：
--
作者：
White RJ;Phares N;Lubin AA;Xiao Y;Plaxco KW
通讯作者：
Plaxco KW