. 2017 Jul 14;121(35):8211–8241. doi: 10.1021/acs.jpcb.7b03441

Table 1. Formal Analogy of the Description of FRET and Anisotropy for Homogeneous Quenching/Rotation in the Absence of Conformational Dynamics^a.

observables	FRET	anisotropy
specific fluorescence intensity decays	f_D\|D^(DA)(t)
specific fluorescence intensity decays	f_D\|D^(D0)(t)
intensity-independent quantifier
species fraction of no FRET molecules/residual anisotropy	x_noFRET	r_∞
direct interpretation of intensity-independent quantifier	ε_D(t) = x_noFRET+∑_ix_RET⁽ⁱ⁾e^{–k_RET⁽ⁱ⁾t}
steady-state quantifier by time-resolved measurements
derived steady-state values for single exponential decays

E is the FRET efficiency eq 1; k_RET is the rate constant of the FRET process eq 9. τ_D(0) = 1/k_D is the lifetime of the donor in the absence of an acceptor, and τ_D(A) = 1/(k_D + k_RET) is the lifetime of the donor in the presence of an acceptor. ε_D(t) is the FRET-induced donor decay. The letters V (vertical) and H (horizontal) represent the polarization of the excitation (first letter) and detection (second letter), respectively. Ideally, the time-resolved anisotropy decay r(t) is obtained by the difference f_Δ and the sum f_∑ of the experimental measurable intensity decays f_VV and f_VH. r is the steady-state anisotropy. ρ is the rotational correlation time.

Table 1. Formal Analogy of the Description of FRET and Anisotropy for Homogeneous Quenching/Rotation in the Absence of Conformational Dynamicsa.

Table 1. Formal Analogy of the Description of FRET and Anisotropy for Homogeneous Quenching/Rotation in the Absence of Conformational Dynamics^a.