ENGINEERED RESIDUE IN CHAIN A, LEU 21 TO MSE ENGINEERED RESIDUE IN CHAIN A, LYS 22 TO ALA ...ENGINEERED RESIDUE IN CHAIN A, LEU 21 TO MSE ENGINEERED RESIDUE IN CHAIN A, LYS 22 TO ALA ENGINEERED RESIDUE IN CHAIN A, LYS 23 TO ALA ENGINEERED RESIDUE IN CHAIN A, LEU 235 TO MSE ENGINEERED RESIDUE IN CHAIN B, LEU 21 TO MSE ENGINEERED RESIDUE IN CHAIN B, LYS 22 TO ALA ENGINEERED RESIDUE IN CHAIN B, LYS 23 TO ALA ENGINEERED RESIDUE IN CHAIN B, LEU 235 TO MSE ENGINEERED RESIDUE IN CHAIN C, LEU 21 TO MSE ENGINEERED RESIDUE IN CHAIN C, LYS 22 TO ALA ENGINEERED RESIDUE IN CHAIN C, LYS 23 TO ALA ENGINEERED RESIDUE IN CHAIN C, LEU 235 TO MSE ENGINEERED RESIDUE IN CHAIN D, LEU 21 TO MSE ENGINEERED RESIDUE IN CHAIN D, LYS 22 TO ALA ENGINEERED RESIDUE IN CHAIN D, LYS 23 TO ALA ENGINEERED RESIDUE IN CHAIN D, LEU 235 TO MSE