The Promoting Vibration in Human Heart Lactate Dehydrogenase Is a Preferred Vibrational Channel
The Promoting Vibration in Human Heart Lactate Dehydrogenase Is a Preferred Vibrational Channel
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DOI：
10.1021/jp210347h
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发表时间：
2011-12-29
影响因子：
3.3
通讯作者：
Schwartz, Steven D.
中科院分区：
文献类型：
--
作者：
Davarifar, Ardy;Antoniou, Dimitri;Schwartz, Steven D.
我们研究乳酸脱氢酶的加速振动是否是热能传递的首选轴。虽然这样一个重要的机械运动也是能量传递的有利方向似乎是合理的，但之前关于酶催化中促进速率的振动的研究都没有解决这个问题。同样有可能的是，促进振动虽然具有重要的催化作用，但与蛋白质中的任何其他轴没有不同的性质。这个问题的解决很重要，有两个原因：首先，如果能量沿着这个轴以一种首选的方式传递，这表明蛋白质被设计成一种将热能转化为与化学步骤相耦合的运动的方式。其次，优选热传递方向的发现为促进振动概念的实验验证提供了一条潜在途径。我们的计算实验是专门设计来模拟潜在的激光实验，在活性位点发色团中沉积热能，随后测量蛋白质中不同点的温度。结果表明，促进振动确实是能量传递的首选通道。此外，我们通过动态结构因子研究了蛋白质的振动结构，表明沿促进振动轴的优先振动运动是蛋白质结构通过热波动的固有性质。
We examine whether the rate-promoting vibration of lactate dehydrogenase is a preferred axis of thermal energy transfer. While it seems plausible that such a mechanistically important motion is also a favored direction of energy transfer, none of the previous studies of rate-promoting vibrations in enzymatic catalysis have addressed this question. It is equally likely that the promoting vibration, though catalytically important, has no different properties than any other axis in the protein. Resolution of this issue is important for two reasons: First, if energy is transferred along this axis in a preferred fashion, it shows that the protein is engineered in a way that transfers thermal energy into a motion that is coupled to the chemical step. Second, the discovery of a preferred direction of thermal transfer provides a potential route to experimental verification of the promoting vibration concept. Our computational experiments are specifically designed to mimic potential laser experiment with the deposition of thermal energy in an active-site chromophore with subsequent measurement of temperature at various points in the protein. Our results indicate that the promoting vibration is indeed a preferred channel of energy transfer. In addition, we study the vibrational structure of the protein via the dynamical structure factor to show preferred vibrational motion along the promoting vibration axis is an inherent property of the protein structure via thermal fluctuations.