Figure 3

Structure and function of T4 internal protein I*. The NMR structure of IP1*, a highly specific inhibitor of the two-subunit CT (gmrS/gmrD) glucosyl-hmC DNA directed restriction endonuclease (right panel); shown are DNA modifications blocking such enzymes. The IPI* structure is compact with an asymmetric charge distribution on the faces (blue are basic residues) that may allow rapid DNA bound ejection through the portal and tail without unfolding-refolding.