Journal Article

Structure and assembly of protocatechuate 3,4-dioxygenase

Lipscomb, J. D., Weber, P. C., Ohlendorf, D. H.

1988

Overview

Dioxygenases catalyse the cleavage of molecular oxygen with subsequent incorporation of both oxygen atoms into organic substrates. Some of the best-studied dioxygenases have been isolated from bacteria where they catalyse the critical ring-opening step in the biodegradation of aromatic compounds. These bacterial enzymes generally contain nonheme ferric iron as the sole cofactor. Protocatechuate 3,4-dioxygenase (3,4-PCD) was one of the first such enzymes recognized and catalyses the intradiol cleavage of protocatechuic acid by oxygen to produce beta-carboxy-cis,cis-muconic acid. Previous studies have shown that the 3,4-PCD found in Pseudomonas aeruginosa is an oligomer with a relative molecular mass (Mr) of 587,000 (587K) containing 12 copies each of alpha (22.3K) and beta (26.6K) subunits. The X-ray structure determination of 3,4-PCD reveals the catalytic iron environment required for oxygenolytic cleavage of aromatic rings and also provides a novel holoenzyme assembly with cubic 23(T) symmetry and first examples of mixed beta-barrel domains.

• Publisher: Nature Publishing,Nature Publishing Group
• Subject: Amino Acid Sequence / Analytical, structural and metabolic biochemistry / Aromatic compounds / Binding Sites / Biodegradation / Biological and medical sciences / Biology / Chemistry / Enzymes and enzyme inhibitors / Fundamental and applied biological sciences. Psychology / Iron / Molecular Sequence Data / Molecular Structure / Oxidoreductases / Oxygen / Oxygenases / Protocatechuate-3,4-Dioxygenase / Pseudomonas aeruginosa