2j74
Structure of Beta-1,4-Galactanase
Structural highlights
FunctionGANB_BACLD Involved in galactan degradation (PubMed:15312766). Degrades arabinose-free galactan to galactooligosaccharides, producing galactotetraose as the main product along with galactotriose, galactobiose, and galactose (PubMed:15312766). May hydrolyze the beta-1,4-galactan linkages of the galactan portion of arabinogalactan type I, a pectic plant polysaccharide from which most of the arabinose has been removed (By similarity).[UniProtKB:O07013][1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMicrobial 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. 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 CT, Christensen LL, Borchert TV, Larsen S, Lo Leggio L Proteins. 2009 Jun;75(4):977-89. PMID:19089956[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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