Fig. 6.

Positions of regulatory sites in thimet oligopeptidase (TOP) mapped to the neurolysin structure. (A) Two 90°-rotated views showing (blue) the positions of the cysteine residues thought to be involved in multimerization of the enzyme. Residue numbers are for neurolysin, with the identity of the neurolysin residue given before the number. Substract one for TOP residue numbers. (B) View of the neurolysin active site showing the nearby cysteine (Cys428) that may be responsible for the sensitivity of both neurolysin and TOP (Cys427) to thiol modifying reagents. The active site zinc (orange sphere) and side-chains of coordinating residues (His474, His478, and Glu503) are shown. This panel was produced with the program RIBBONS (Carson 1987). (C) Position of the TOP serine (residue 644) phosphorylated by protein kinase A.