Table 1.
Dissociation constants of Cbl-IIa/b riboswitches
| Riboswitch | KD1,Adoa | KD1,Mea | Krel1b | KD2,Mea | Krel2b |
|---|---|---|---|---|---|
| nm | nm | nm | |||
| env8Cbl-IIa | >1e7c | 6 ± 3 | >2e5c | 480 ± 40 | >2000c |
| env4Cbl-IIa | >1e7c | 44 ± 23 | >2e5c | 3000 ± 1000 | >300c |
| T. elongatus cbiX Cbl-IIa | 2700 ± 400 | 17 ± 3 | 200 | 300 ± 70 | 7 |
| A. marina hupE Cbl-IIa | 6900 ± 100 | 510 ± 300 | 10 | ||
| env62CblIIa | 110 ± 20 | 56 ± 20 | 2 | ||
| S. elongatus hupE Cbl-IIa | 640 ± 50 | 3800 ± 3000 | 0.2 | ||
| env127Cbl-IIa | 200 ± 30 | 1000 ± 300 | 0.2 | ||
| env47Cbl-IIa | 440 ± 30 | 4200 ± 1000 | 0.1 | ||
| env77Cbl-IIa | 890 ± 200 | 7700 ± 2000 | 0.1 | ||
| env50Cbl-IIa | 6.2 ± 5.0 | 140 ± 10 | 0.04 | ||
| E. faecalis eutG Cbl-IIb | 100 ± 40 | 36,000 ± 20,000 | 0.003 |
a Binding affinities are shown as the average ± S.D. from three independent titrations. For env8Cbl-IIa, env4Cbl-IIa, and T. elongatus cbiX Cbl-IIa riboswitches, the values for KD1 and KD2 were calculated using a multiple ligand-binding model.
b Krel = (KD,Ado)/(KD,Me).
c The values are based upon an estimate of the minimum value for KD based upon the ITC measurements.