Calculation of transition dipole moment in fluorescent proteins-towards efficient energy transfer
Calculation of transition dipole moment in fluorescent proteins-towards efficient energy transfer
复制标题
DOI：
10.1039/c2cp23351g
复制
发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Shurki, Avital
中科院分区：
文献类型：
--
作者：
Ansbacher, Tamar;Srivastava, Hemant Kumar;Shurki, Avital
荧光蛋白之间的共振能量转移（FRET）被广泛用于构建荧光传感蛋白、研究细胞内蛋白质间的相互作用以及监测多结构域蛋白质的构象变化。尽管FRET强烈依赖于供体和受体荧光团的跃迁偶极矩（TDM）的取向，但这种取向依赖性目前在FRET传感器设计中没有考虑。类似地，使用FRET来推导结构约束的研究通常假设kappa（2）为2/3或使用绿色荧光蛋白的TDM，因为这是唯一已经通过实验确定TDM的FP。在这里，我们使用时间依赖密度泛函理论（TD-DFT）方法来计算TDM的一个全面的列表中常用的荧光蛋白。该方法在更高水平的计算中得到了验证。用模型化合物和实验确定的GFP的TDM的验证表明，TDM主要由π-缀合的荧光团的结构确定，并且对非缀合的侧链或周围的蛋白质不敏感。我们的计算不仅提供了TDM目前使用的FP，但也提出了一个经验规则，可用于获得TDM的新开发的荧光蛋白在未来。
Forster Resonance Energy Transfer (FRET) between fluorescent proteins (FPs) is widely used to construct fluorescent sensor proteins, to study intracellular protein-protein interactions and to monitor conformational changes in multidomain proteins. Although FRET depends strongly on the orientation of the transition dipole moments (TDMs) of the donor and acceptor fluorophores, this orientation dependence is currently not taken into account in FRET sensor design. Similarly, studies that use FRET to derive structural constrains typically assume a kappa(2) of 2/3 or use the TDM of green fluorescent protein, as this is the only FP for which the TDM has been determined experimentally. Here we used time-dependent density functional theory (TD-DFT) methods to calculate the TDM for a comprehensive list of commonly used fluorescent proteins. The method was validated against higher levels of calculation. Validation with model compounds and the experimentally determined TDM of GFP shows that the TDM is mostly determined by the structure of the pi-conjugated fluorophore and is insensitive to non-conjugated side chains or the protein surrounding. Our calculations not only provide TDM for most of the currently used FPs, but also suggest an empirical rule that can be used to obtain the TDMs for newly developed fluorescent proteins in the future.