Regulation of phenolic catabolism in Rhizobium leguminosarum biovar trifolii.
In members of the family Rhizobiaceae, many phenolic compounds are degraded by the protocatechuate branch of the beta-ketoadipate pathway. In this paper we describe a novel pattern of induction of protocatechuate (pca) genes in Rhizobium leguminosarum biovar trifolii. Isolation of pca mutant strains revealed that 4-hydroxybenzoate, quinate, and 4-coumarate are degraded via the protocatechuate pathway. At least three inducers govern catabolism of 4-hydroxybenzoate to succinyl coenzyme A and acetyl coenzyme A. The enzyme that catalyzes the initial step is induced by its substrate, whereas the catabolite beta-carboxy-cis,cis-muconate induces enzymes for the upper protocatechuate pathway, and beta-ketoadipate elicits expression of the enzyme for a subsequent step, beta-ketoadipate succinyl-coenzyme A transferase. Elucidation of the induction pattern relied in part on complementation of mutant Rhizobium strains by known subclones of Acinetobacter genes expressed off the lac promoter in a broad-host-range vector.
Parke
D
D
Department of Biology, Yale University, New Haven, Connecticut 06511-8112.
Rynne
F
F
Glenn
A
A
D000105:Acetyl Coenzyme A / Q000096:biosynthesis / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000096:biosynthesis / Q000378:metabolism; D000272:Adipates / Q000378:metabolism; D062385:Hydroxybenzoates / Q000378:metabolism; D009154:Mutation; D010226:Parabens / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D010957:Plasmids; D015183:Restriction Mapping; D012231:Rhizobium / Q000378:metabolism*
D000214:Acyl Coenzyme A; D000272:Adipates; D062385:Hydroxybenzoates; D010226:Parabens; D010636:Phenols; C027316:3-oxoadipic acid; C009091:protocatechuic acid; D000105:Acetyl Coenzyme A; C012046:succinyl-coenzyme A; C038193:4-hydroxybenzoic acid