Figure 4

Spatial conservation of the PD-(D/E)XK active site in all3650, Hjc, and NgoMVI. A) The predicted structure of all360 is shown in the same orientation as the crystal structures of the bona fide PD-(D/E)XK nucleases: B) Holliday junction resolvase Hje (1ob8 in PDB [9]) and C) REase NgoMIV (1fiu in PDB [78] to illustrate the spatial conservation of side-chains in the active site (the carboxylate residues in red and the Lys residue in blue), despite the lack of their conservation in the PD-EXX-K, PD-DXK, and PD-XXK-E variants of the sequence motif. Only the common core is shown, terminal regions and insertions have been omitted for clarity of the presentation.