21 4A zinc finger motif is a ○ ● ○ DNA-binding domain ooO +自 90000 OO Figure 21. 5 The first finger of a DNA binding Dimerization steroid receptor controls specificity of dNA-binding (positions shown in red); the second finger controls specificity of dimerization(positions shown in blue). The expanded view of the first finger shows that ■■■■■■ discrimination between GRE and Glucocorticoid Estrogen ERE target sequences rests on specificity spec ificity two amino acids at the base Same sequence in both receptors lO Different sequence in each receptor 请莘大Figure 21.5 The first finger of a steroid receptor controls specificity of DNA-binding (positions shown in red); the second finger controls specificity of dimerization (positions shown in blue). The expanded view of the first finger shows that discrimination between GRE and ERE target sequences rests on two amino acids at the base. 21.4 A zinc finger motif is a DNA-binding domain