Figure 4 - full size

Figure 4.
Figure 4 Structural details of T-ag interaction with DNA bases in the PEN-2 and PEN-4 structures. (A) Sequence-specific interaction of Arg 154 with G1 (the first G in the GAGGC pentamer) in the PEN-4 structure. A representative electron density map (shown in blue) is superimposed on the model. (B) Nonspecific interaction of Arg 154 with A1 (A in position of G1) in the PEN-2 structure. A representative electron density is superimposed on Arg 154. (C) Sequence-specific interaction of Ser 152 with A2. (D) Nonspecific interaction of Ser 152 with the T2 in the PEN-2 structure. Sequence-specific interactions, which involve (E) the G3 and Asn 153, (F) the G4 and Asn 153, and (G) the G (complementary to C5) with Arg 204. The protein and DNA are shown as stick models and colored by atom type; yellow for carbon, blue for nitrogen, red for oxygen, and purple for phosphorus. A representative electron density as captured from 2F[o]-F[c] map is shown with contours drawn at the 1.25 level. Hydrogen bonds are indicated with red dashed lines, and the length of the bonds is indicated in Å.