Figure 2: (a) An alignment of the cyclin boxes of S. cerevisiae G1 and G1/S cyclins. The bars above the sequence show the postulated positions of the helices of the cyclin box based on structural modeling in S. cerevisiae G1/S cyclins Cln1 and Cln2. (b) Predicted second structure of of the cyclin boxes of S. cerevisiae G1 and G1/S cyclins. Regions predicted as helix and β-strand are indicated as ‘‘H’’ or ‘‘E’’, respectively.