Ghasemi Fatemeh, Shafiee Afshin
Research Group on Foundations of Quantum Theory and Information, Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran, Iran.
Research Group on Foundations of Quantum Theory and Information, Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran, Iran; School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran.
Biosystems. 2019 Oct;184:103988. doi: 10.1016/j.biosystems.2019.103988. Epub 2019 Jul 5.
The role of quantum tunneling in altering the structure of nucleotides to each other and causing a mutational event in DNA has been a topic of debate for years. Here, we introduce a new quantum mechanical approach for analyzing a typical point-mutation in DNA strands. Assuming each codon as a base state, a superposition of codon states could provide a physical description for a set of codons encoding the same amino acid and there are transition amplitudes between them. We choose the amino acids Phe and Ile as our understudy bio-systems which are encoded by two and three codons, respectively. We treat them as large quantum systems and use double- and triple-well potential models to study the fundamental behaviors of them in interaction with a harmonic environment. We use the perturbation theory to calculate the transition probabilities between the codons which encoding the same amino acid and determine the transition rates of some point mutations. Moreover, we evaluate the quantum biological channel capacity for these transitions to show that the channel capacity depends on the system-environment interaction via the dissipation factor Γ. The obtained results demonstrate that the tunneling rate is under the control of capacity of the corresponding biological channel. In other words, the reduction in quantum channel capacity prevents the quantum tunneling rate to be increased.
多年来，量子隧穿在改变核苷酸彼此结构并导致DNA发生突变事件中的作用一直是一个争论的话题。在此，我们引入一种新的量子力学方法来分析DNA链中的典型点突变。假设每个密码子为一个基态，密码子态的叠加可以为一组编码相同氨基酸的密码子提供一种物理描述，并且它们之间存在跃迁振幅。我们选择苯丙氨酸（Phe）和异亮氨酸（Ile）作为我们研究的生物系统，它们分别由两个和三个密码子编码。我们将它们视为大型量子系统，并使用双阱和三阱势模型来研究它们与谐波环境相互作用时的基本行为。我们使用微扰理论来计算编码相同氨基酸的密码子之间的跃迁概率，并确定一些点突变的跃迁速率。此外，我们评估这些跃迁的量子生物通道容量，以表明通道容量通过耗散因子Γ取决于系统 - 环境相互作用。所得结果表明，隧穿速率受相应生物通道容量的控制。换句话说，量子通道容量的降低会阻止量子隧穿速率增加。
