Table 2. Course of the cordycepin aptamer selection.

Round	RNA quantity (nmol)	[RNA] (μM)	Pre-selection	Percentage of input RNA eluted with
				ATP	Cordycepin
1	11	2	Yes	—	<0.5
2	2.5	1	Yes	—	0.5
3	0.35	0.2	Yes	1.4	<0.1
4	0.35	0.2	Yes	—	19.5
5	0.2	0.1	Yes	19	1
6a	0.2	0.1	Yes		<0.1

^aOn round 6, cordycepin agarose was diluted with Tris-derivatized sepharose to a final concentration of 5 pmol cordycepin/ml sepharose. An aliquot of 200 μl of cordycepin sepharose were used.