Physically associated enzymes produce and metabolize 2-hydroxy-2,4-dienoate, a chemically unstable intermediate formed in catechol metabolism via meta cleavage in Pseudomonas putida.

The meta-cleavage pathway of catechol is a major mechanism for degradation of aromatic compounds. In this pathway, the aromatic ring of catechol is cleaved by catechol 2,3-dioxygenase and its product, 2-hydroxymuconic semialdehyde, is further metabolized by either a hydrolytic or dehydrogenative route. In the dehydrogenative route, 2-hydroxymuconic semialdehyde is oxidized to the enol form of 4-oxalocrotonate by a dehydrogenase and then further metabolized to acetaldehyde and pyruvate by the actions of 4-oxalocrotonate isomerase, 4-oxalocrotonate decarboxylase, 2-oxopent-4-enoate hydratase, and 4-hydroxy-2-oxovalerate aldolase.

X-ray crystallographic structure of dienelactone hydrolase at 2.8 A.

The structure of dienelactone hydrolase, an enzyme of the beta-ketoadipate pathway, has been determined at 2.8 A resolution using multiple isomorphous replacement techniques. An unambiguous assignment of C alpha atoms to electron density has been accomplished and a preliminary identification of the active site made.

Abundant expression of Pseudomonas genes for chlorocatechol metabolism.

The respective specific activities of catechol 1,2-oxygenase II (catechol 1,2-dioxygenase; EC 1.13.11.

Cloning and genetic organization of the pca gene cluster from Acinetobacter calcoaceticus.

The beta-ketoadipate pathway of Acinetobacter calcoaceticus comprises two parallel metabolic branches. One branch, mediated by six enzymes encoded by the cat genes, converts catechol to succinate and acetyl coenzyme A (acetyl-CoA); the other branch, catalyzed by products of the pca genes, converts protocatechuate to succinate and acetyl-CoA by six metabolic reactions analogous or identical to those of the catechol sequence. We used the expression plasmid pUC18 to construct expression libraries of DNA from an A.

Nucleotide sequence and expression of clcD, a plasmid-borne dienelactone hydrolase gene from Pseudomonas sp. strain B13.

The clcD structural gene encodes dienelactone hydrolase (EC 3.1.1.

Dienelactone hydrolase from Pseudomonas sp. strain B13.

Dienelactone hydrolase (EC 3.1.1.

Crystallization and preliminary x-ray crystallographic data of dienelactone hydrolase from Pseudomonas sp. B13.

Dienelactone hydrolase (EC 3.1.1.

Crystal structure of muconate lactonizing enzyme at 6.5 A resolution.

We have obtained crystals of Pseudomonas putida muconate lactonizing enzyme. They diffract to better than 2.4 A resolution and have two monomers in the asymmetric unit, related by a non-crystallographic 2-fold axis.

Enzymes of the beta-ketoadipate pathway in Pseudomonas putida: primary and secondary kinetic and equilibrium deuterium isotope effects upon the interconversion of (+)-muconolactone to cis,cis-muconate catalyzed by cis,cis-muconate cycloisomerase.

Primary and secondary kinetic and secondary equilibrium deuterium isotope effect studies on the cis,cis-muconate cycloisomerase catalyzed interconversion of cis,-cis-muconate (CCM) and (+)-muconolactone (ML) have been performed. The primary and solvent kinetic deuterium isotope effects upon Vmax for the reactions of (+)-[5R-2H]muconolactone in water (HOH) and (+)-muconolactone in deuterium oxide (DOD) to form cis,cis-muconate are about 2.5-2.

Enzymes of the beta-ketoadipate pathway in Pseudomonas putida: kinetic and magnetic resonance studies of the cis,cis-muconate cycloisomerase catalyzed reaction.

Steady-state kinetic analysis of the divalent metal ion requiring cis,cis-muconate cycloisomerase catalyzed interconversion of cis,cis-muconate and (+)-muconolactone obeys Michaelis-Menten kinetics and the Haldane relationship from pH 6.2 to 8.3.