Table 1.

Progress of selection

Round	pmol RNA initially bound**	[tobramycin]	% of bound RNA eluted by tobramycin
1	170	100 μM	1.6
2	180		1.2
3	202		1.7
4	205		2.5
5	151		2.5
6	187		2.5
7	212		3.5
8	196		2.7
9	179		6.4
10	93		10
11	62		17
12	68		16
13	71		16
*12–2	67	20 μM	8.0
*13–2	64		11
14	51		11
*14–2	63	4 μM	5.9
15	55		4.9
16	62		3.4

^*RNA eluted in round 11 was used in round 12 and in round 12–2. RNA eluted in round 12–2 was used in round 13–2. RNA eluted in round 13–2 was used in round 14 and in round 14–2.

^**The amount of bound RNA was calculated as the amount of RNA eluted by tobramycin plus the amount of RNA eluted by buffer at 65°C.