TABLE 1.

Spectroscopic parameters determined for the 14-bp duplexes bearing the TATAAAAG and TITIIIIG “TATA Box” sequences

Sequence	*	(RET)min†	(RET)max‡	§	Eb§	¶
TATAAAAG	1.35	0.71	0.79	0.44	0.66	0.77
TITIIIIG	2.13	0.44	0.57	0.23	0.42

^* is the ratio of the extinction coefficients of TAMRA (T) and fluorescein (F) at the indicated wavelengths for the double-labeled duplexes.

^†(R_ET)_min (calculated from Eq. 5) is the parameter R_ET for the free double-labeled duplexes.

^‡(R_ET)_max is the parameter R_ET for the TBP-bound double-labeled duplexes (see Fig. 4).

^§E_f and E_b (calculated from Eq. 6) are the energy transfer efficiencies from fluorescein to TAMRA for the free and TBP-bound double-labeled duplexes, respectively.

^¶ is the relative affinity of TBP for two sequences in the experimental buffer free of osmolyte, where K_d(A) and K_d(I) are the dissociation constants of TBP for the TATAAAAG and TITIIIIG sequences, respectively.