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Updated: Jun 22, 2026

Crystallization and Structural Determination of an Enzyme:Substrate Complex by Serial Crystallography in a Versatile Microfluidic Chip
Published on: March 20, 2021
Crystal structures of g-type lysozyme from Atlantic cod shed new light on substrate binding and the catalytic
Ronny Helland1, Renate L Larsen, Solrun Finstad
1Department of Chemistry, The Norwegian Structural Biology Centre, University of Tromsø, 9037 Tromsø, Norway. Ronny.Helland@uit.no
Abstract:
Crystal structures of Atlantic cod lysozyme have been solved with and without ligand bound in the active site to 1.7 and 1.9 A resolution, respectively. The structures reveal the presence of NAG in the substrate binding sites at both sides of the catalytic Glu73, hence allowing the first crystallographic description of the goose-type (g-type) lysozyme E-G binding sites. In addition, two aspartic acid residues suggested to participate in catalysis (Asp101 and Asp90) were mutated to alanine. Muramidase activity data for two single mutants and one double mutant demonstrates that both residues are involved in catalysis, but Asp101 is the more critical of the two. The structures and activity data suggest that a water molecule is the nucleophile completing the catalytic reaction, and the roles of the aspartic acids are to ensure proper positioning of the catalytic water.
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