FIG 8.

Phosphorylation sites of ICP27-CTD. In vitro phosphorylation assays using PKA, CKII, and PKC kinases, followed by analysis using mass spectrometry revealed several phosphorylated sites in ICP27-CTD (shown in orange). Molecule 1 is depicted in gray, and molecule 2 is depicted in light pink. (A) Many of the observed sites were concentrated in the flexible loop capping the C-tail, mainly S290, S311, T314, and S321. Considering the high flexibility of the capping loop, there exists a possibility of phosphorylation-induced local conformation changes. (B) Most other sites are concentrated in the region in close to the zinc-binding motif, mainly S266, S268, S272, T478, S484, S485, and S493.