Entry retrieved from the Protein Data Bank at RCSB.

1LMQ: Hydrolase (O-Glycosyl). Date: Oct 25, 1994.
Authors: S.Karlsen, E.Hough
Compound: Lysozyme. Source: Oncorhynchus Mykiss.
Ligand: Tetra-N-Acetylglucosamine (Tetra NAG)
Method: X-Ray Diffraction. Resolution:1.6 Ang.

Lysozyme is an enzyme that facilitates the destruction of cell walls that are composed of alternating NAM (N-acetylmuramic acid) and NAG (N-acetylglucosamine) units. Lysozyme does so by way of electrostatic catalysis of NAM-NAG bond cleavage. Asp 52 and Glu 35 are key to the catalytic action: (1) Asp 52 (shown in spacefill) contains a carboxylate side chain and its negative charge stabilizes the incipient positive charge on NAM in the cleavage. (2) Glu 35 (shown in spacefill) contains a carboxylic acid side chain and this acid acts as a general acid catalyst. Find Asp 52 and Glu 35 in the binding pocket.