RESULTS AND DISCUSSION
The NMP binding site in the catalytic center. X-ray diffraction
analysis of PAN crystals soaked with rUMP/rAMP/TMP
and divalent cations under the conditions described in Materials
and Methods revealed extra density around the catalytic
site of the PAN endonuclease, suggesting that the affinity of
PAN for nucleosides is therefore sufficiently high in the presence
of Mg2 (Fig. 1).