Functional importance analysis for the nucleotides within the non-substrate binding domain of E3 (A1-A26) by point-mutation. The cleavage of FRQ30 by each mutant was carried out at 23 C in OC for both 1 h and 24 h at E/S ratio =10 : 1. %Clv at 1 h was used to derive the relative activity at 1 h (RA1h) as follows: RA1h of mutant=100x(%Clv of mutant at 1 h)/(%Clv of E3 at 1 h). Coloring Scheme for the functional importance of a nucleotide: red, RA1h=0 and RA24h<5; purple, RA1h=0–10 but RA24h at 10 or greater; green, RA1h=10–70; grey: RA1h>70. Error bars represent mean plus SD for at least two independent experiments.
