Project description:α-L-arabinofuranosidases (EC 3.2.1.55) participate in the degradation of a variety of L-arabinose-containing polysaccharides and interact synergistically with other hemicellulases in the production of oligosaccharides and bioconversion of lignocellulosic biomass into biofuels. In this work, the structure of a novel thermostable family 51 (GH51) α-L-arabinofuranosidase from Thermotoga petrophila RKU-1 (TpAraF) was determined at 3.1 Å resolution. The TpAraF tertiary structure consists of an (α/β)-barrel catalytic core associated with a C-terminal β-sandwich domain, which is stabilized by hydrophobic contacts. In contrast to other structurally characterized GH51 AraFs, the accessory domain of TpAraF is intimately linked to the active site by a long β-hairpin motif, which modifies the catalytic cavity in shape and volume. Sequence and structural analyses indicate that this motif is unique to Thermotoga AraFs. Small angle X-ray scattering investigation showed that TpAraF assembles as a hexamer in solution and is preserved at the optimum catalytic temperature, 65°C, suggesting functional significance. Crystal packing analysis shows that the biological hexamer encompasses a dimer of trimers and the multiple oligomeric interfaces are predominantly fashioned by polar and electrostatic contacts.
Project description:The endo-1,5-alpha-L-arabinanases belonging to glycoside hydrolase family 43 are of great industrial interest for use in food technology, organic synthesis and biofuel production owing to their ability to catalyze the hydrolysis of alpha-1,5-arabinofuranosidic bonds in arabinose-containing polysaccharides. In this work, Thermotoga petrophila endo-1,5-alpha-L-arabinanase, a GH43-family member, has been cloned, overexpressed, purified and crystallized. Single crystals were obtained from a solution containing 0.1 M MES buffer pH 6.5, 0.8 M ammonium sulfate, 0.1 M EDTA, 0.1 M L-proline and 5%(v/v) dioxane. X-ray diffraction data were collected to a resolution of 2.86 A using synchrotron radiation and the diffraction pattern was indexed in the tetragonal space group P422, with unit-cell parameters a = b = 83.71, c = 408.25 A.
