Identification of the Adenovirus E4orf4 Protein Binding Site on the B55α and Cdc55 Regulatory Subunits of PP2A: Implications for PP2A Function, Tumor Cell Killing and Viral Replication
Figure 1
(A) Sequence alignment of B55α and Cdc55. Alignment is in relation to the crystal structure of B55α. The positions (or proposed positions for Cdc55) of β-strands within blades 1 to 7 (e.g., β1a, etc.), the β-hairpin loops (b1 to b4), and the β-hairpin arm are indicated above the sequences. Highlighted residues correspond to amino acids subjected to mutational analysis in β55α (top sequence) and Cdc55 (bottom sequence) and are listed in Tables 1 and 2, respectively. (B) Known B55α structure shown in ribbon and surface depictions with the putative substrate binding groove of B55α indicated. (C) Predicted Cdc55 structure (as generated by ModWeb) shown in ribbon and surface depictions. Highlighted in dark gray are residues that are most divergent from B55α in the primary sequence, as shown in (A).