Role of side-edge site of sphingomyelinase from Bacillus cereus

► Bc-SMase requires a divalent metal ion for membrane binding. ► The side-edge of Bc-SMase plays an important role in membrane binding. ► Asn57, Glu99, and Asp100 at the side-edge are essential for the folding metal ion. ► The amino acid residues of the side-edge have no effect on enzymatic activity.