Table 1.
Characteristics of B2+ and B2− sequences
| Best match to ACS/11 | Helical stability | No. of As/11 | No. of Ts/11 | |
|---|---|---|---|---|
| Avg. of B2+ sequences | 7.4 ± 0.9 | 5.3 ± 1.6 Kcal/mol | 5.6 ± 1.4 | 2.8 ± 1.3 |
| Avg. of B2− sequences | 4.5 ± 1.2 | 7.9 ± 3.6 Kcal/mol | 2.5 ± 1.4 | 3.9 ± 1.5 |
| Avg. of random library sequences | 4.6 ± 1.1 | 8.2 ± 5.3 Kcal/mol | 2.7 ± 1.2 | 3.2 ± 1.5 |
| Avg. of randomly generated A-rich sequences | 6.4 ± 1.7 | 6.2 ± 1.7 Kcal/mol | 5.4 ± 1.6 | 2.3 ± 1.2 |
| P value B2+ vs. random | 3.3E-05 | 6.6E-08 | 2.9E-11 | 0.27 |
| P value B2− vs. random | 0.91 | 0.53 | 0.42 | 0.080 |
| P value B2+ vs. random A-rich | 8.8E-05 | 0.0060 | 0.52 | 0.041 |
Best match to ACS is either at the defined B2 element position or shifted one base pair to the left (based on Fig. 1). Helical stability was calculated for the 13 bp including the B2 element using the WebThermodyn program and the data sets of SantaLucia et al. (29, 30). P values are the result of two-tailed Student t tests. P values in italics are considered significant.