3WDV: The Complex Structure Of Ptlic16a With Cellotetraose

Citation:
Abstract
The thermostable 1,3-1,4-beta-glucanase PtLic16A from the fungus Paecilomyces thermophila catalyzes stringent hydrolysis of barley beta-glucan and lichenan with an outstanding efficiency and has great potential for broad industrial applications. Here, we report the crystal structures of PtLic16A and an inactive mutant E113A in ligand-free form and in complex with the ligands cellobiose, cellotetraose and glucotriose at 1.80A to 2.25A resolution. PtLic16A adopts a typical beta-jellyroll fold with a curved surface and the concave face forms an extended ligand binding cleft. These structures suggest that PtLic16A might carry out the hydrolysis via retaining mechanism with E113 and E118 serving as the nucleophile and general acid/base, respectively. Interestingly, in the structure of E113A/1,3-1,4-beta-glucotriose complex, the sugar bound to the -1 subsite adopts an intermediate-like (alpha-anomeric) configuration. By combining all crystal structures solved here, a comprehensive binding mode for a substrate is proposed. These findings not only help understand the 1,3-1,4-beta-glucanase catalytic mechanism but also provide a basis for further enzymatic engineering.
PDB ID: 3WDVDownload
MMDB ID: 121269
PDB Deposition Date: 2013/6/25
Updated in MMDB: 2014/07
Experimental Method:
x-ray diffraction
Resolution: 1.94  Å
Source Organism:
Similar Structures:
Biological Unit for 3WDV: monomeric; determined by author and by software (PISA)
Molecular Components in 3WDV
Label Count Molecule
Protein (1 molecule)
1
Beta-1,3-1,4-glucanase
Molecule annotation
Chemicals (3 molecules)
1
1
2
2
* Click molecule labels to explore molecular sequence information.

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