Watrob Heather M, Pan Chia-Pin, Barkley Mary D
Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-7078, USA.
J Am Chem Soc. 2003 Jun 18;125(24):7336-43. doi: 10.1021/ja034564p.
The power of FRET to study molecular complexes is expanded by the use of two or more donor/acceptor pairs. A general theoretical framework for distance measurements in three-chromophore systems is presented. Three energy transfer schemes applicable to many diverse situations are considered: (I) two-step FRET relay with FRET between the first and second chromophores and between the second and third, (II) FRET from a single donor to two different acceptors, and (III) two-step FRET relay with FRET also between the first and third chromophores. Equations for the efficiencies involving multiple energy transfer steps are derived for both donor quenching and sensitized emission measurements. The theory is supported by experimental data on model systems of known structure using steady-state donor quenching, lifetime quenching, and sensitized emission. The distances measured in the three-chromophore systems agree with those in two-chromophore systems and molecular models. Finally, labeling requirements for diagnosis of the energy transfer scheme and subsequent distance measurements are discussed.
通过使用两个或更多供体/受体对，荧光共振能量转移（FRET）研究分子复合物的能力得到了扩展。本文提出了一个用于三发色团系统距离测量的通用理论框架。考虑了适用于多种不同情况的三种能量转移方案：（I）第一步和第二步发色团之间以及第二步和第三步发色团之间进行荧光共振能量转移的两步FRET中继，（II）从单个供体到两个不同受体的荧光共振能量转移，以及（III）第一步和第三步发色团之间也进行荧光共振能量转移的两步FRET中继。针对供体猝灭和敏化发射测量，推导了涉及多个能量转移步骤的效率方程。该理论得到了使用稳态供体猝灭、寿命猝灭和敏化发射的已知结构模型系统实验数据的支持。在三发色团系统中测量的距离与两发色团系统和分子模型中的距离一致。最后，讨论了诊断能量转移方案和后续距离测量的标记要求。
