Analysis of Hydrogen Tunneling in an Enzyme Active Site using von Neumann Measurements.
Analysis of Hydrogen Tunneling in an Enzyme Active Site using von Neumann Measurements.
复制标题
使用冯诺依曼测量分析酶活性位点中的氢隧道。
DOI：
10.1021/ct900630n
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发表时间：
2010
影响因子：
5.5
通讯作者：
Iyengar,SrinivasanS
中科院分区：
文献类型：
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作者：
Sumner,Isaiah;Iyengar,SrinivasanS
我们建立在我们早期的量子波包研究中的生物酶大豆脂肪氧合酶-1的氢转移，通过使用冯诺依曼量子测量理论，以获得定性的见解转移事件。我们把酶的活性位点作为一个测量装置，通过它在每个配置施加的电位作用于隧穿氢核。在隧穿过程中的一系列变化的活性位点的几何形状的影响的初始，反应物状态到最终的，产品状态的顺序投影。我们研究这个过程中使用几种不同的冯诺依曼测量和显示如何离散序列的这种测量不仅逐步增加的投影的氢核波包到产品侧，但也有利于质子的氘转移。在波包动力学研究中发现的氢隧穿问题的几个定性特征也恢复在这里。这些包括作为核量子化的结果的“过渡态”向反应物的转移，在氘的情况下激发态的更大参与，以及沿着反应坐标沿着存在促进氢和氘转移并与表面交叉重合的临界点。为了进一步“定制”的动态，我们构建了一个扰动的测量序列，这是一个扰动的动态序列的活性位点的几何形状的演变，这使我们洞察存在的敏感区域的反应曲线的活性位点的动态的微妙变化可以有影响的氢和氘的转移过程。
We build on our earlier quantum wavepacket study of hydrogen transfer in the biological enzyme soybean lipoxygenase-1 by using von Neumann quantum measurement theory to gain qualitative insights into the transfer event. We treat the enzyme active site as a measurement device which acts on the tunneling hydrogen nucleus via the potential it exerts at each configuration. A series of changing active site geometries during the tunneling process effects a sequential projection of the initial, reactant state onto the final, product state. We study this process using several different kinds of von Neumann measurements and show how a discrete sequence of such measurements not only progressively increases the projection of the hydrogen nuclear wavepacket onto the product side but also favors proton over deuteron transfer. Several qualitative features of the hydrogen tunneling problem found in wavepacket dynamics studies are also recovered here. These include the shift in the “transition state” toward the reactant as a result of nuclear quantization, greater participation of excited states in the case of deuterium, and the presence of critical points along the reaction coordinate that facilitate hydrogen and deuterium transfer and coincide with surface crossings. To further “tailor” the dynamics, we construct a perturbation to the sequence of measurements, that is a perturbation to the dynamical sequence of active site geometry evolution, which leads us to insight on the existence of sensitive regions of the reaction profile where subtle changes to the dynamics of the active site can have an effect on the hydrogen and deuterium transfer process.