title: Crystallization and preliminary crystallographic analysis of Abp, a GH27 β-L-arabinopyranosidase from Geobacillus stearothermophilus.
abstract: Geobacillus stearothermophilus T-6 is a thermophilic soil bacterium that possesses an extensive system for the utilization of hemicellulose. The bacterium produces a small number of endo-acting extracellular enzymes that cleave high-molecular-weight hemicellulolytic polymers into short decorated oligosaccharides, which are further hydrolysed into the respective sugar monomers by a battery of intracellular glycoside hydrolases. One of these intracellular processing enzymes is β-L-arabinopyranosidase (Abp), which is capable of removing β-L-arabinopyranose residues from naturally occurring arabino-polysaccharides. As arabino-polymers constitute a significant part of the hemicellulolytic content of plant biomass, their efficient enzymatic degradation presents an important challenge for many potential biotechnological applications. This aspect has led to an increasing interest in the biochemical characterization and structural analysis of this and related hemicellulases. Abp from G. stearothermophilus T-6 has recently been cloned, overexpressed, purified, biochemically characterized and crystallized in our laboratory, as part of its complete structure-function study. The best crystals obtained for this enzyme belonged to the primitive orthorhombic space group P2(1)2(1)2(1), with average unit-cell parameters a = 107.7, b = 202.2, c = 287.3 Å. Full diffraction data sets to 2.3 Å resolution have been collected for both the wild-type enzyme and its D197A catalytic mutant from flash-cooled crystals at 100 K, using synchrotron radiation. These data are currently being used for a high-resolution three-dimensional structure determination of Abp.
authors.affiliation: Institute of Chemistry and the Laboratory for Structural Chemistry and Biology, Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
authors.forename: Shifra
authors.initials: S
authors.lastname: Lansky
authors.forename: Rachel
authors.initials: R
authors.lastname: Salama
authors.forename: Vered H
authors.initials: VH
authors.lastname: Solomon
authors.forename: Hassan
authors.initials: H
authors.lastname: Belrhali
authors.forename: Yuval
authors.initials: Y
authors.lastname: Shoham
authors.forename: Gil
authors.initials: G
authors.lastname: Shoham
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; D011135:Polysaccharides, Bacterial; D006026:Glycoside Hydrolases; C019716:beta-L-arabinosidase
keywords: GH27; Geobacillus stearothermophilus; arabinopyranosidase; catalytic mutant; glycoside hydrolase