Fig. 2.

The mapping of HDX patterns to the crystal structure of WT COMT. Shown is the structure of a ternary complex of COMT with AdoMet cofactor and dinitrocatechol substrate (PDB ID code 3BWM) (36) with the following color scheme for HDX in WT enzyme: type I, cyan; type II-A, yellow; type II-B, raspberry. Mg²⁺ metal is in orange. Because the reported HDX experiments represent the apo protein, we have shown the AdoMet and substrate as thin lines rather than the usual stick representation (see Fig. 4). Data for the region containing the site of mutation (gray) were not complete, but, based on two temperatures, appeared to correspond to type I behavior (see text).