Fig. 2: Model of the CDK2-cyclin A-CDC25A complex.

a Structure of the CDK2-cyclin A-CDC25A complex (PDB 8ROZ) in the same orientation and colour depiction as Fig. 1e, showing overall quaternary architecture and binding of CDC25A. Zoomed panel depicts the CDC25A C-terminal helix (EM density threshold 0.248) which binds at the CDK2-cyclin A interface. Superposition of CDK2-cyclin A-CDC25A (grey) with existing (b) CDK2-cyclin A crystal structure (PDB 1JST⁵⁸, CDK2 in blue and cyclin A depicted in orange) and (c) CDC25A crystal structure (PDB 1C25³⁷, pink). The helical secondary structure of the CDC25A C-terminal domain observed in the cryo-EM structure, spanning residues Glu495-Leu524 (shown in green), is not observed in the CDC25A crystal structure which terminates at Glu495 (labelled in c).