... indicatethat the region between amino acids 28 and 139 of DEC1(including the bHLH domain) is sufficient for the suppressive activity of DEC1. The C-terminal region(amino acids 140–412), including the ... conclude that the basic region, p artic-ularly the conserved A rg65, but not His57, is essential for the suppressive activity of DEC1.Determination of the binding domain of DEC1 to BMAL1 The interaction ... connected to the DEC1 E-boxes(Fig. 2), while deletion of the Orange domain ( DEC1DOr-ange) had no effect on the suppressive activity, indicating the importance of t he bHLH region of DEC1. The HXXXXXXXR...