Hasegawa Jun-Ya, Fujimoto Kazuhiro, Swerts Ben, Miyahara Tomoo, Nakatsuji Hiroshi
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
J Comput Chem. 2007 Nov 30;28(15):2443-52. doi: 10.1002/jcc.20667.
Excited states of fluorescent proteins were studied using symmetry-adapted cluster-configuration interaction (SAC-CI) method. Protein-environmental effect on the excitation and fluorescence energies was investigated. In green fluorescent protein (GFP), the overall protein-environmental effect on the first excitation energy is not significant. However, glutamine (Glu) 94 and arginine (Arg96) have the red-shift contribution as reported in a previous study (Laino et al., Chem Phys 2004, 298, 17). The excited states of GFP active site (GFP-W22-Ser205-Glu222-Ser65) were also calculated. Such large-scale SAC-CI calculations were performed with an improved code containing a new algorithm for the perturbation selection. The SAC-CI results indicate that a charge-transfer state locates at 4.19 eV, which could be related to the channel of the photochemistry as indicated in a previous experimental study. We also studied the excitation and fluorescence energies of blue fluorescent protein, cyan fluorescent protein, and Y66F. The SAC-CI results are very close to the experimental ones. The protonation state of blue fluorescent protein was determined. Conformation of cyan fluorescent protein indicated by the present calculation agrees to the experimentally observed structure.
使用对称适配簇-组态相互作用（SAC-CI）方法研究了荧光蛋白的激发态。研究了蛋白质-环境对激发能和荧光能的影响。在绿色荧光蛋白（GFP）中，蛋白质-环境对第一激发能的总体影响并不显著。然而，如先前研究（Laino等人，《化学物理》，2004年，298卷，17页）所报道，谷氨酰胺（Glu）94和精氨酸（Arg96）有红移贡献。还计算了GFP活性位点（GFP-W22-Ser205-Glu222-Ser65）的激发态。这种大规模的SAC-CI计算是使用包含用于微扰选择的新算法的改进代码进行的。SAC-CI结果表明，一个电荷转移态位于4.19 eV，这可能与先前实验研究中指出的光化学通道有关。我们还研究了蓝色荧光蛋白、青色荧光蛋白和Y66F的激发能和荧光能。SAC-CI结果与实验结果非常接近。确定了蓝色荧光蛋白的质子化状态。本计算表明的青色荧光蛋白的构象与实验观察到的结构一致。
