fig2

Figure 2. Comparison of different TP901-1 CI-NTD structures. (A) Aromatic residues Tyr3, Tyr5, Trp43, and Phe67 of TP901-1 Mor form a cavity in which Gln55 from CI must fit for complex formation; (B) the conformation of Glu69 in the structures of CI without Mor would cause severe clashes with Phe67 of Mor in the complex; (C) the structures of the C-terminal region from Asp76 to Val80 are similar in CI-NTD alone (5A7L, 8QAO from this manuscript) and in the complex with Mor (6TRI). The CI-NTD:Mor complex structure is shown in light green (CI) and teal (Mor) cartoon representation with green sticks for highlighted side chains. The shown sticks are from CI-NTD containing structures 3ZHI (light blue), 3ZHM (yellow), 5A7L (grey), and 8QAO from this manuscript (salmon). CI-NTD: N-terminal domain of Phage repressor.