Quantum origins of molecular recognition and olfaction in drosophila
Quantum origins of molecular recognition and olfaction in drosophila
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DOI：
10.1063/1.4767067
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发表时间：
2012-12-14
影响因子：
4.4
通讯作者：
Roman, Gregg
中科院分区：
文献类型：
--
作者：
Bittner, Eric R.;Madalan, Adrian;Roman, Gregg
气味剂分子识别的标准模型是受体位点通过分子几何形状进行区分，这证明两种手性分子可能具有非常不同的气味。然而，最近的研究同位素标记的嗅觉表明，可能有一个分子振动传感组件的嗅觉接收，特别是在光谱区域约2300 cm（-1）。在这里，我们提出了一个供体桥受体模型的嗅觉，试图解释这种效果。我们的模型，基于准确的量子化学计算的嗅觉剂（桥）在其中性和电离状态，假定的嗅觉剂的内部模式被激发脉冲在空穴传输过程中从供体受体上的受体网站，特别是那些模式是共振的隧道间隙。通过将冲击力投影到内部模式上，我们可以确定在给定的施主-受主隧穿间隙值下哪些模式被激发。只有那些与隧穿间隙共振并被脉冲激发的模式才会对非弹性传输率做出显著贡献。以苯乙酮为例，我们的模型和实验对D. Melanogaster的研究表明，给定嗅觉剂的同位素异构体产生不同的气味性质。这些结果支持的概念，非弹性散射效应可能发挥作用，在同位素异构体之间的区别，但这不是一个一般的光谱效应。(C)2012年美国物理学会。[http：//dx.doi.org/10.1063/1.4767067]
The standard model for molecular recognition of an odorant is that receptor sites discriminate by molecular geometry as evidenced that two chiral molecules may smell very differently. However, recent studies of isotopically labeled olfactants indicate that there may be a molecular vibration-sensing component to olfactory reception, specifically in the spectral region around 2300 cm(-1). Here, we present a donor-bridge-acceptor model for olfaction which attempts to explain this effect. Our model, based upon accurate quantum chemical calculations of the olfactant (bridge) in its neutral and ionized states, posits that internal modes of the olfactant are excited impulsively during hole transfer from a donor to acceptor site on the receptor, specifically those modes that are resonant with the tunneling gap. By projecting the impulsive force onto the internal modes, we can determine which modes are excited at a given value of the donor-acceptor tunneling gap. Only those modes resonant with the tunneling gap and are impulsively excited will give a significant contribution to the inelastic transfer rate. Using acetophenone as a test case, our model and experiments on D. melanogaster suggest that isotopomers of a given olfactant give rise to different odorant qualities. These results support the notion that inelastic scattering effects may play a role in discriminating between isotopomers but that this is not a general spectroscopic effect. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767067]