Virtuelle (Nano) Welten: PDB Molecule of the Month 9: Lysozyme

A Molecular Laboratory

Lysozyme is a small, stable enzyme, making ideal for research into protein structure and function. Brian Matthews at the University of Oregon has performed a remarkable series of experiments, using lysozyme as the laboratory for study. He has performed hundreds of mutations on the lysozyme molecule made by a bacteriophage, changing one or more amino acids in the protein chain to a different one. He has studied the effect of removing large residues inside the protein, leaving a hole, or cramming a large amino acid inside, where it would not normally fit. He has attempted to create new active sites by creating new molecule-shaped pockets. Structures of hundreds of these mutant lysozymes are available at the PDB- -so many, in fact, that lysozyme is the most common protein in the PDB. The example shown here is a mutant where two amino acids (shown in green) have been changed to cysteine, forming a new disulfide bridge (the two bright yellow atoms) in the mutant. The native enzyme, from PDB entry 1lyd, is on the left and the mutant, from PDB entry 1l35, is on the right.