ORIENTATIONAL FREEDOM OF MOLECULAR PROBES - ORIENTATION FACTOR IN INTRA-MOLECULAR ENERGY-TRANSFER
ORIENTATIONAL FREEDOM OF MOLECULAR PROBES - ORIENTATION FACTOR IN INTRA-MOLECULAR ENERGY-TRANSFER
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DOI：
10.1016/s0006-3495(79)85243-1
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发表时间：
1979-01-01
影响因子：
3.4
通讯作者：
BLUMBERG, WE
中科院分区：
文献类型：
--
作者：
DALE, RE;EISINGER, J;BLUMBERG, WE
测量附着在同一大分子基质上的供体 (D) 和受体 (A) 发光体之间的 Forster 长程共振能量转移效率，可用于估计 D-A 分离 R。如果 D 和 A 跃迁偶极子在比转移时间（动态平均条件）更短的时间内对相对于基质的所有方向（各向同性条件）进行采样，则平均值 取向因子[.kappa.2]为2/3。如果不满足各向同性条件，但动态平均条件是，[κ2]的上限和下限，以及因此R，可以从观察到的D和A去极化获得，并且如果转移去极化也已知，则可以进一步缩小这些限制。提出了用于获得这种重新定向信息的实验方案以及作为一般可观察到的去极化的函数的[.kappa.2]min 和[.kappa.2]min 的等高线图。这允许将不确定性分配给所确定的R值。不需要知道D和A重新取向过程的细节，但假设取向分布相对于静止基底至少具有近似轴对称性。针对各种取向分布函数导出平均去偏振因子，该函数证明了发光体重新取向的各种机制的影响。一般来说，静态平均机制不适合确定 R。
The measurement of the efficiency of Forster long-range resonance energy transfer between donor (D) and acceptor (A) luminophores attached to the same macromolecular substrate can be used to estimate the D-A separation, R. If the D and A transition dipoles sample all orientations with respect to the substrate (the isotropic condition) in a time that is short compared with the transfer time (the dynamic averaging condition), the average orientation factor [.kappa.2] is 2/3. If the isotropic condition is not satisfied, but the dynamic averaging condition is, upper and lower bounds for [.kappa.2], and thus R, may be obtained from observed D and A depolarizations, and these limits may be further narrowed if the transfer depolarization is also known. Experimental protocols for obtaining this reorientational information and contour plots of [.kappa.2]min and [.kappa.2]min as functions of generally observable depolarizations are presented. This permits an uncertainty to be assigned to the determined value of R. The details of the D and A reorientational process need not be known, but the orientational distributions are assumed to have at least approximate axial symmetry with respect to a stationary substrate. Average depolarization factors are derived for various orientational distribution functions that demonstrate the effects of various mechanisms for reorientation of the luminophores. In general the static averaging regime does not lend itself to determinations of R.