Purification, crystallization and X-ray diffraction analysis of a novel ring-cleaving enzyme (BoxC_C) from Burkholderia xenovorans LB400

The assimilation of aromatic compounds by microbial species requires specialized enzymes to cleave the thermodynamically stable ring. In the recently discovered benzoate-oxidation (box) pathway in Burkholderia xenovorans LB400, this is accomplished by a novel dihydrodiol lyase (BoxC_C). Sequence analysis suggests that BoxC_C is part of the crotonase superfamily but includes an additional uncharacterized region of approximately 115 residues that is predicted to mediate ring cleavage. Processing of X-ray diffraction data to 1.5 Å resolution revealed that BoxC_C crystallized with two molecules in the asymmetric unit of the P2₁2₁2₁ space group, with a solvent content of 47% and a Matthews coefficient of 2.32 Å³ Da^-1. Selenomethionine BoxC_C has been purified and crystals are currently being refined for anomalous dispersion studies.