TABLE 1.

Selected SELEX sequences from Taq and Exo⁻Kl

Namea	Primer-template sequenceb	Kd,app,gelshift (nM)c
Random starting material	5′-gcctgcaggtcgactctagaNNNNNNNNNNNNNNNNNNNNN-3′	>200 (Taq)
	3′-cggacgtccagctgagatctNNNNNNNNNNNNNNNNNNNNNNNNN-5′	>500 (Exo−Kl)
Taq1	5′-gcctgcaggtcgactctagaCCCAGTCCACACTAAAGCATA-3′	36 ± 6
	3′-cggacgtccagctgagatctGGGTCAGGTGTGATTTCGTATCTGT-5′
Taq2	5′-gcctgcaggtcgactctagaCCCCAATTTGCGAACGTGCCT-3′	6.3 ± 0.1
	3′-cggacgtccagctgagatctGGGTCAGGTGTGATTTCGTATCAGC-5′
Exo−Kl-1	5′-gcctgcaggtcgactctagaCAACCATCGAAGACTA-3′	125 ± 25
	3′-cggacgtccagctgagatctGTTGGTAGCTTCTGATATCGTCCGT-5′

^aRandom starting material was the starting material for the SELEX process. Selected sequences with Exo⁻Kl contained a BbsI restriction site (underlined) derived from the random region of the starting material that produced a 9-base 5′ overhang leading the Exo⁻Kl-1 sequence shown (see Results).

^bLowercase letters are bases derived from the fixed region of the starting material, while bases derived from the random region are capitalized. “N” signifies that the base was random in the starting material (either A, T, C, or G), while “N” is the complement of that base in the template strand.

^cAffinities measured in gel shift assays were measured with 2 nM primer-template starting material and under the conditions described in Materials and Methods. The derived K_d values were useful for comparisons between these sequences and various modifications presented in the text but were not determined under conditions that would necessarily yield accurate K_d values. Therefore, they are referred to as apparent K_d values that are specific for the gel shift experiment (K_{d,app,gelshift}). Results were averages from at least 3 experiments ± SD.