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Nature. 1988 Nov 24;336(6197):403-5.

Structure and assembly of protocatechuate 3,4-dioxygenase.

Author information

1
E. I. du Pont de Nemours and Co., Central Research and Development Department, Wilmington, Delaware 19880-0228.

Abstract

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.

PMID:
3194022
DOI:
10.1038/336403a0
[Indexed for MEDLINE]

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