Table 4. Dissociation constants (Kd) in mol/L and associated errors of mutated ACCTAC (AC1 element) sequences.
| Kd | Error | |
| ACCTAC | 9.12E-09 | 3.11E-09 |
| GCCTAC | >5.00E-06 | |
| AGCTAC | >5.00E-06 | |
| ACGTAC | >5.00E-06 | |
| ACCGAC | 7.19E-07 | 2.12E-07 |
| ACCTGC | 7.97E-08 | 1.83E-08 |
| ACCTAG | 5.60E-08 | 5.09E-09 |
A guanine nucleotide was inserted one nucleotide at a time and shifted along the AC1 motif. Relative binding affinities of the mutated AC1 elements to AtMYB61 were determined by a nitrocellulose filter-binding assay. The relative binding affinities were used to determine the dissociation constants of the CASTing targets by GRAFIT program which linearised the nonlinear regression via scatchard plots to calculate the point at which half of the ligand was bound to AtMYB61. Underlined bases correspond to a substituted guanine.