5A8O

Crystal structure of beta-glucanase SdGluc5_26A from Saccharophagus degradans in complex with cellotetraose

Summary for 5A8O

• Entry DOI: 10.2210/pdb5a8o/pdb
• Related: 5A8M 5A8N 5A8P 5A8Q 5A94
• Related PRD ID: PRD_900011
• Descriptor: PUTATIVE RETAINING B-GLYCOSIDASE, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, CHLORIDE ION, ... (8 entities in total)
• Functional Keywords: hydrolase, cazyme, glycoside hydrolase, beta-glucanase, gh5_26
• Biological source: SACCHAROPHAGUS DEGRADANS 2-40
• Total number of polymer chains: 1
• Total formula weight: 44191.46

Authors

Sulzenbacher, G.,Lafond, M.,Freyd, T.,Henrissat, B.,Coutinho, R.M.,Berrin, J.G.,Garron, M.L. (deposition date: 2015-07-16, release date: 2016-01-20, Last modification date: 2024-01-10)

Primary citation

Lafond, M.,Sulzenbacher, G.,Freyd, T.,Henrissat, B.,Berrin, J.G.,Garron, M.L.
The Quaternary Structure of a Glycoside Hydrolase Dictates Specificity Towards Beta-Glucans
J.Biol.Chem., 291:7183-, 2016

PubMed Abstract: In the Carbohydrate-Active Enzyme (CAZy) database, glycoside hydrolase family 5 (GH5) is a large family with more than 6,000 sequences. Among the 51 described GH5 subfamilies, subfamily GH5_26 contains members that display either endo-β(1,4)-glucanase or β(1,3;1,4)-glucanase activities. In this study, we focused on the GH5_26 enzyme fromSaccharophagus degradans(SdGluc5_26A), a marine bacterium known for its capacity to degrade a wide diversity of complex polysaccharides.SdGluc5_26A displays lichenase activity toward β(1,3;1,4)-glucans with a side cellobiohydrolase activity toward β(1,4)-glucans. The three-dimensional structure ofSdGluc5_26A adopts a stable trimeric quaternary structure also observable in solution. The N-terminal region ofSdGluc5_26A protrudes into the active site of an adjacent monomer. To understand whether this occupation of the active site could influence its activity, we conducted a comprehensive enzymatic characterization ofSdGluc5_26A and of a mutant truncated at the N terminus. Ligand complex structures and kinetic analyses reveal that the N terminus governs the substrate specificity ofSdGluc5_26A. Its deletion opens the enzyme cleft at the -3 subsite and turns the enzyme into an endo-β(1,4)-glucanase. This study demonstrates that experimental approaches can reveal structure-function relationships out of reach of current bioinformatic predictions.

PubMed: 26755730
DOI: 10.1074/JBC.M115.695999

Experimental method

X-RAY DIFFRACTION (2.3 Å)