Structural highlights
5a95 is a 3 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | BGC, CL, MG, NA, TRS |
| Related: | 5a8m, 5a8n, 5a8o, 5a8p, 5a8q, 5a94 |
| Activity: | Licheninase, with EC number 3.2.1.73 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum |
Publication Abstract from PubMed
In the 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- beta(1,4)-glucanase or beta(1,3;1,4)-glucanase activities. In this study, we focused on the GH5_26 enzyme from Saccharophagus degradans (SdGluc5_26A) a marine bacterium known for its capacity to degrade a wide diversity of complex polysaccharides. SdGluc5_26A displays lichenase activity towards beta(1,3;1,4)-glucans with a side cellobiohydrolase activity towards beta(1,4)-glucans. The 3D structure of SdGluc5_26A adopts a stable trimeric quaternary structure observable also in solution. The N-terminal region of SdGluc5_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 of SdGluc5_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 of SdGluc5_26A. Its deletion opens the enzyme cleft at the -3 subsite and turns the enzyme into an endo-beta(1,4)-glucanase. This study demonstrates that experimental approaches can reveal structure-function relationships out of reach of current bioinformatic predictions.
the quaternary structure of a glycoside hydrolase dictates specificity towards beta-glucans.,Lafond M, Sulzenbacher G, Freyd T, Henrissat B, Berrin JG, Garron ML J Biol Chem. 2016 Jan 11. pii: jbc.M115.695999. PMID:26755730[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lafond M, Sulzenbacher G, Freyd T, Henrissat B, Berrin JG, Garron ML. the quaternary structure of a glycoside hydrolase dictates specificity towards beta-glucans. J Biol Chem. 2016 Jan 11. pii: jbc.M115.695999. PMID:26755730 doi:https://dx.doi.org/10.1074/jbc.M115.695999
