Figure 2.

a) Position of arginine and Asp 128 (123 according PDB file 1RLA) in wild type arginase.
b) Position of substrate and Asn 128 in mutant AspAs. Note the position of the amide group assumed in Asn 128 in relation to carboxyl group of Asp 128. Mn²⁺ ions are shown in purple for reference.