Fig. 4From: Acute Intermittent Porphyria: Expression of Mutant and Wild-Type Porphobilinogen Deaminase in COS-1 CellsA model of PBGD constructed from the refined coordinates of the E. coli enzyme. The mutation R211G (corresponding to the human mutation R225G) is located on the outer surface of the polypeptide and disrupts the hydrogen bond with aspartic acid at position 3. a, active site of the enzyme.Back to article page