Dolghih Elena, Ortiz Wilfredo, Kim Seonah, Krueger Brent P, Krause Jeffrey L, Roitberg Adrian E
Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, Florida 32611-8435, USA.
J Phys Chem A. 2009 Apr 23;113(16):4639-46. doi: 10.1021/jp811395r.
FRET experiments enable studies of the chemical and physical properties of individual molecules, which has long been a dream of chemists. However, these modern experimental techniques are still limited by the lack of information about the dynamic behavior of the fluorescent labels as well as by the use of dipole-dipole approximation even at short donor-to-acceptor distances. Our results help to suggest that these assumptions need to be carefully considered when designing experiments. We show that at short donor-acceptor separation, dipole-dipole approximation breaks down and Forster theory fails and cannot be used to obtain correct distances. We also explicitly demonstrate that dyes' linkers allow for a lot of flexibility in the fluorescent label orientation and position resulting in distances much shorter than assumed earlier.
荧光共振能量转移（FRET）实验能够对单个分子的化学和物理性质进行研究，这长期以来一直是化学家们的梦想。然而，这些现代实验技术仍然受到限制，一方面是缺乏有关荧光标记动态行为的信息，另一方面即使在供体-受体距离较短时仍使用偶极-偶极近似法。我们的研究结果表明，在设计实验时需要仔细考虑这些假设。我们发现，在供体-受体间距较短时，偶极-偶极近似法不再适用，福斯特理论失效，无法用于获得正确的距离。我们还明确证明，染料连接体在荧光标记的方向和位置上具有很大的灵活性，导致距离比之前假设的要短得多。
