Crystal structure of an aromatic ring opening dioxygenase LigAB, a protocatechuate 4,5-dioxygenase, under aerobic conditions.
Sugimoto, K., Senda, T., Aoshima, H., Masai, E., Fukuda, M., Mitsui, Y.(1999) Structure 7: 953-965
- PubMed: 10467151 
- DOI: https://doi.org/10.1016/s0969-2126(99)80122-1
- Primary Citation of Related Structures:  
1B4U, 1BOU - PubMed Abstract: 
Sphingomonas paucimobilis SYK-6 utilizes an extradiol-type catecholic dioxygenase, the LigAB enzyme (a protocatechuate 4,5-dioxygenase), to oxidize protocatechuate (or 3,4-dihydroxybenzoic acid, PCA). The enzyme belongs to the family of class III extradiol-type catecholic dioxygenases catalyzing the ring-opening reaction of protocatechuate and related compounds. The primary structure of LigAB suggests that the enzyme has no evolutionary relationship with the family of class II extradiol-type catecholic dioxygenases. Both the class II and class III enzymes utilize a non-heme ferrous center for adding dioxygen to the substrate. By elucidating the structure of LigAB, we aimed to provide a structural basis for discussing the function of class III enzymes.
Organizational Affiliation: 
Department of BioEngineering, Nagaoka University of Technology, Niigata, Japan.