Characterization of crystals of protocatechuate 3,4-dioxygenase from Pseudomonas cepacia.

Protocatechuate 3,4-dioxygenase (EC 1.13.11.3) from Pseudomonas cepacia (Mr = 198,000) has been crystallized from potassium phosphate at pH 7.5. Of the two orthorhombic forms that have been characterized, one contains a single molecule of tetrameric protocatechuate dioxygenase, (alpha beta Fe3+)4, per asymmetric unit. The space group and cell dimensions for this form are: P2(1)2(1)2(1) with a = 125.9 A, b = 161.7 A, and c = 85.2 A.