Figure 1.

Structures of the Ub and PCNA fusions. (A) Schematic diagrams of the Ub fusion constructs to the N-terminus (top) or C-terminus (bottom) of PCNA-164R. (B) Molecular structure of the PCNA homotrimer from both front and side views shown at left and right, respectively. (C) Predicted PCNA-Ub structures for the N- and C-terminal fusions as well as the in vivo PCNA-Lys164 monoubiquitylation, The PDB file for PCNA (1AXC) (52) was used to generate the molecular structure. Each subunit of the PCNA homotrimer is colored differently and the natural Ub modification site at Lys164 is in yellow. The N- and C-terminal residues of PCNA are colored blue and red, respectively.