Investigating the Binding of Beta-1,4-Galactan to Bacillus Licheniformis Beta-1,4-Galactanase by Crystallography and Computational Modeling.Le Nours, J., De Maria, L., Welner, D., Jorgensen, C.T., Christensen, L.L.H., Borchert, T.V., Larsen, S., Lo Leggio, L.
(2009) Proteins 75: 977
- PubMed: 19089956
- DOI: 10.1002/prot.22310
- Primary Citation of Related Structures:
- PubMed Abstract:
Microbial beta-1,4-galactanases are glycoside hydrolases belonging to family 53, which degrade galactan and arabinogalactan side chains in the hairy regions of pectin, a major plant cell wall component. They belong to the larger clan GH-A of glycosid ...
Microbial beta-1,4-galactanases are glycoside hydrolases belonging to family 53, which degrade galactan and arabinogalactan side chains in the hairy regions of pectin, a major plant cell wall component. They belong to the larger clan GH-A of glycoside hydrolases, which cover many different poly- and oligosaccharidase specificities. Crystallographic complexes of Bacillus licheniformis beta-1,4-galactanase and its inactive nucleophile mutant have been obtained with methyl-beta(1-->4)-galactotetraoside, providing, for the first time, information on substrate binding to the aglycone side of the beta-1,4-galactanase substrate binding groove. Using the experimentally determined subsites as a starting point, a beta(1-->4)-galactononaose was built into the structure and subjected to molecular dynamics simulations giving further insight into the residues involved in the binding of the polysaccharide from subsite -4 to +5. In particular, this analysis newly identified a conserved beta-turn, which contributes to subsites -2 to +3. This beta-turn is unique to family 53 beta-1,4-galactanases among all clan GH-A families that have been structurally characterized and thus might be a structural signature for endo-beta-1,4-galactanase specificity.
Biophysical Chemistry Group, Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark.