Rational design of supramolecular hemin/G-quadruplex-dopamine aptamer nucleoapzyme systems with superior catalytic performance.
Rational design of supramolecular hemin/G-quadruplex-dopamine aptamer nucleoapzyme systems with superior catalytic performance.
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DOI：
10.1039/c5sc04832j
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发表时间：
2016-05-01
期刊：
影响因子：
8.4
通讯作者：
Willner I
中科院分区：
文献类型：
--
作者：
Albada HB;Golub E;Willner I
我们设计了超分子nucleapzyme系统，利用计算机模拟显示增强的多巴胺氧化能力，并开发了一个系统具有可切换的催化活性。一组氯化血红素/G-四链体（hGQ）-多巴胺结合适体（DBA）共轭物，作为核适酶的合理设计，进行了描述。核结合酶构建体由作为催化单元的hGQ DNA酶和作为底物结合单元的DBA组成，它们通过由互补寡核苷酸链组成的双链体支架而在空间上接近。当hGQ单元通过可变长度的单链DNA系链连接到双链体支架时，与由分离的hGQ和DBA单元刺激的过程相比，所得核适酶显示出对H2 O2介导的多巴胺氧化为氨基色素的适度催化增强（5-7倍增强）。这种有限的增强归因于hGQ相对于多巴胺结合位点的不适当的空间定位，和/或将hGQ催化位点连接到双链支架的系链的柔性。为了解决这个问题，通过将hGQ锚在与DBA单元相关的双链体结构域上的三链体寡核苷酸结构实现了hGQ/DBA缀合物的刚性化。通过hGQ/DBA结构的顺序的、程序化的、三重控制的刚性化，鉴定了对多巴胺氧化成氨基色素具有上级催化活性的核apzyme（30倍催化增强）。分子动力学模拟表明，在产生的高活性硬化核apzym结构中，hGQ催化位点在空间上靠近DBA底物结合位点的开口，从而合理化并支持该系统增强的催化功能。最后，使最活跃的核适酶系统经受燃料链和反燃料链，所述燃料链和反燃料链分离并重新组装核适酶结构，允许核适酶催化功能的“开”和“关”切换。
We designed supramolecular nucleoapzyme systems displaying enhanced dopamine-oxidizing abilities using computational simulations, and developed a system having switchable catalytic activities. The rational design of a set of hemin/G-quadruplex (hGQ)–dopamine binding aptamer (DBA) conjugates, acting as nucleoapzymes, is described. The nucleoapzyme constructs consist of a hGQ DNAzyme as a catalytic unit and DBA as a substrate binding unit that are brought into spatial proximity by a duplex scaffold composed of complementary oligonucleotide strands. When the hGQ unit is linked to the duplex scaffold via a single-strand DNA tether of variable length, the resulting nucleoapzymes reveal a moderate catalytic enhancement toward the H2O2-mediated oxidation of dopamine to aminochrome as compared to the process stimulated by the separated hGQ and DBA units (5–7 fold enhancement). This limited enhancement is attributed to inappropriate spatial positioning of the hGQ in respect to the dopamine binding site, and/or to the flexibility of the tether that links the hGQ catalytic site to the double-stranded scaffold. To solve this, rigidification of the hGQ/DBA conjugates by triplex oligonucleotide structures that anchor the hGQ to a duplex domain associated with the DBA units was achieved. By the sequential, programmed, triplex-controlled rigidification of the hGQ/DBA structure, a nucleoapzyme with superior catalytic activity toward the oxidation of dopamine to aminochrome is identified (30-fold catalytic enhancement). Molecular dynamics simulations reveal that in the resulting highly active rigidified nucleoapzyme structure, the hGQ catalytic site is positioned in spatial proximity to the opening of the DBA substrate binding site, thus rationalizing and supporting the enhanced catalytic functions of the system. Finally, the most active nucleoapzyme system was subjected to fuel- and anti-fuel strands that separate and re-assemble the nucleoapzyme structure, allowing “ON” and “OFF” switching of the nucleoapzyme catalytic functions.
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