Autolysis loop, K698 localization, and predicted phosphorylation sites in the structure of μPlg. The structure is viewed with PyMOL software. The backbone is presented as a ribbon diagram and the Autolysis Loop is colored in red. Side chain colors follows: K698 (purple), R561 (purple), active side triad (H603, D646, S741) (cyan), and the predicted mammalian phosphorylation sites (yellow). The active site serine (S741) was replaced with Alanine (A741) in the structure. A. Wild type μPlm. B. A model of K698Q mutant. The side chain for the Q residue is in silver color.