Loco Daniele, Buda Francesco, Lugtenburg Johan, Mennucci Benedetta
Dipartimento di Chimica e Chimica Industriale , University of Pisa , via G. Moruzzi 13 , 56124 , Pisa , Italy.
Leiden Institute of Chemistry , Leiden University , Einsteinweg 55 , 2300 RA Leiden , The Netherlands.
J Phys Chem Lett. 2018 May 3;9(9):2404-2410. doi: 10.1021/acs.jpclett.8b00763. Epub 2018 Apr 25.
Understanding the microscopic origin of the color tuning in pigment-protein complexes is a challenging yet fundamental issue in photoactive biological systems. Here, we propose a possible interpretation by using a state-of-the-art multiscale strategy based on the integration of quantum chemistry and polarizable atomistic embeddings into a dynamic description. By means of such a strategy we are able to resolve the long-standing dispute over the coloration mechanism in the crustacyanin protein. It is shown that the combination of the dynamical flexibility of the carotenoid pigments (astaxanthin) with the responsive protein environment is essential to obtain quantitative predictions of the spectral tuning. The strong linear correlation between the excitation energies and the bond length alternation in the long-chain carotenoids modulated by the dynamical protein environment is a novel finding explaining the high color tunability in crustacyanin.
理解色素 - 蛋白质复合物中颜色调谐的微观起源是光活性生物系统中一个具有挑战性但又至关重要的问题。在此，我们基于将量子化学和可极化原子嵌入整合到动态描述中的先进多尺度策略，提出一种可能的解释。通过这种策略，我们能够解决关于虾青素蛋白中着色机制的长期争议。结果表明，类胡萝卜素色素（虾青素）的动态灵活性与响应性蛋白质环境的结合对于获得光谱调谐的定量预测至关重要。由动态蛋白质环境调节的长链类胡萝卜素中激发能与键长交替之间的强线性相关性是一个新发现，解释了虾青素蛋白中的高颜色可调性。
