FIGURE 6.
UNG/Ugi interaction. A, the structure of the hUNG/Ugi complex is shown (35). Ugi is shown in stick representation together with its surface in mesh representation (cyan carbon atoms). Residue Leu-272 of the intercalation loop is shown in space-filling representation (green). hUNG is shown in stick representation with dark green carbon atoms. B, Ugi is represented as in A. Arg-185 of His-D4-A201–50 (yellow) is shown in space-filling representation after manual superposition of equivalent atoms of the intercalation loop with its hUNG counterpart. The rest of D4 is shown in yellow stick representation. Note the clash of the larger arginine residue with the leucine-binding pocket of Ugi and the absence of hydrogen bond partners for the charged guanidinium group within the hydrophobic binding pocket.