2jie

File:2jie.jpg

spinqualitylabelsall models 2jie, resolution 2.3Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

BETA-GLUCOSIDASE B FROM BACILLUS POLYMYXA COMPLEXED WITH 2-F-GLUCOSE

OverviewOverview

Bacteria species involved in degradation of cellulosic substrates produce, a variety of enzymes for processing related compounds along the hydrolytic, pathway. Paenibacillus polymyxa encodes two homologous beta-glucosidases, BglA and BglB, presenting different quaternary structures and substrate, specificities. We previously reported the 3D-structure of BglA, which is, highly specific against cellobiose. Here, we present structural analysis, of BglB, a monomeric enzyme that acts as an exo-beta-glucosidase, hydrolyzing cellobiose and cellodextrins of higher degree of, polymerization. The crystal structure of BglB shows that several polar, residues narrow the active site pocket and contour additional subsites., The structure of the BglB-cellotetraose complex confirms these subsites, revealing the substrate-binding mode, and shows the oligosaccharide-enzyme, recognition pattern in detail. Comparison between BglA and BglB crystal, structures suggests that oligomerization in BglA can assist in fine-tuning, the specificity of the active centre by modulating the loops surrounding, the cavity. We have solved the crystal structure of BglB with bound, thiocellobiose, a competitive inhibitor, which together with the, BglB-cellotetraose complex delineate the general features of the aglycon, site. The detailed characterization of the atomic interactions at the, aglycon site show a recognition pattern common to all bacterial, beta-glucosidases, and presents some differences with the aglycon site in, plant beta-glycosidases essentially by means of a different orientation of, the basal Trp. The crystal structures of of BglB with a covalently bound, inhibitor (derived from 2-fluoroglucoside) and glucose (produced by, hydrolysis of the substrate in the crystal), provide additional pictures, of the binding events and the intermediates formed during the reaction., Altogether, this information can assist in the understanding of subtle, differences of the enzyme mechanism and substrate recognition within this, family of enzymes, and consequently it can help in the development of new, enzymes with improved activity or specificity.

About this StructureAbout this Structure

2JIE is a Single protein structure of sequence from Paenibacillus polymyxa with G2F as ligand. Active as Beta-glucosidase, with EC number 3.2.1.21 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

ReferenceReference

Crystal Structures of Paenibacillus polymyxa beta-Glucosidase B Complexes Reveal the Molecular Basis of Substrate Specificity and Give New Insights into the Catalytic Machinery of Family I Glycosidases., Isorna P, Polaina J, Latorre-Garcia L, Canada FJ, Gonzalez B, Sanz-Aparicio J, J Mol Biol. 2007 Aug 31;371(5):1204-18. Epub 2007 Jun 2. PMID:17585934

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