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 A resolution revealed that BoxC(C) crystallized with two molecules in the asymmetric unit of the P2(1)2(1)2(1) space group, with a solvent content of 47% and a Matthews coefficient of 2.32 A(3) Da(-1). Selenomethionine BoxC(C) has been purified and crystals are currently being refined for anomalous dispersion studies.