Cloning, purification and preliminary crystallographic analysis of Ara127N, a GH127 β-l-arabinofuranosidase from Geobacillus stearothermophilus T6

The l-arabinan utilization system of Geobacillus stearothermophilus T6 is composed of five transcriptional units that are clustered within a 38 kb DNA segment. One of the transcriptional units contains 11 genes, the last gene of which (araN) encodes a protein, Ara127N, that belongs to the newly established GH127 family. Ara127N shares 44% sequence identity with the recently characterized HypBA1 protein from Bifidobacterium longum and thus is likely to function similarly as a β-l-arabinofuranosidase. β-l-Arabinofuranosidases are enzymes that hydrolyze β-l-arabinofuranoside linkages, the less common form of such linkages, a unique enzymatic activity that has been identified only recently. The interest in the structure and mode of action of Ara127N therefore stems from its special catalytic activity as well as its membership of the new GH127 family, the structure and mechanism of which are only starting to be resolved. Ara127N has recently been cloned, overexpressed, purified and crystallized. Two suitable crystal forms have been obtained: one (CTP form) belongs to the monoclinic space group P21, with unit-cell parameters a = 104.0, b = 131.2, c = 107.6 Å, β = 112.0°, and the other (RB form) belongs to the orthorhombic space group P212121, with unit-cell parameters a = 65.5, b = 118.1, c = 175.0 Å. A complete X-ray diffraction data set has been collected to 2.3 Å resolution from flash-cooled crystals of the wild-type enzyme (RB form) at −173°C using synchrotro...
Source: Acta Crystallographica Section F - Category: Biochemistry Authors: Tags: Geobacillus stearothermophilus glycoside hydrolase β -arabinofuranosidase, GH127 arabinose arabinofuranoside arabinan utilization selenomethionine MAD SAD crystallization communications Source Type: research