20 likes | 154 Vues
This study explores direct titration by fluorescent polarization to analyze DNA interactions. The anisotropy values for free and fully bound DNA are derived from the equation A = Af - (Ab - Af)((D + E + Kd) - √((D + E + Kd)² - 4DE))/2D. The dissociation constants (Kd) for FAM-AniI and FAM-SceI are calculated as 17.71 ± 2.33 nM and 19.78 ± 3.34 nM respectively. Additionally, competitive titration is utilized to determine unlabeled DNA concentrations, revealing Ki values of 51.56 ± 20.37 nM and 120.8 ± 23.18 nM.
E N D
Direct titration by fluorescent polarization A = Af - (Ab-Af)[(D+E+Kd)-{(D+E+Kd)2-4DE}1/2]/2D A, anisotropy; Af, anisotropy of the free DNA; Ab, anisotropy of the fully bound DNA; D, the DNA concentration; E, the enzyme concentration. Kd (FAM-AniI wt DNA) = 17.71 ± 2.33 nM Kd (FAM-SceI wt DNA) = 19.78 ± 3.34 nM
Competitive titration X (Bound/Free)= (A-Af)/(Ab-A) C = {1+Ki/(KdX)}[E-D{X/(1+X)}-KdX] A, anisotropy; Af, anisotropy of the free DNA; Ab, anisotropy of the fully bound DNA; C, the unlabled DNA concentration; D, the labled DNA concentration; E, the enzyme concentration. Ki (Unlabled AniI wt DNA) = 51.56 ± 20.37 nM Ki (Unlabled SceI wt DNA) = 120.8 ± 23.18 nM