Caister Academic Press

Spotlight on the Acinetobacter baylyi Beta-Ketoadipate Pathway: Multiple Levels of Regulation

Ulrike Gerischer, Bettina Jerg and Rita Fischer
from: Acinetobacter Molecular Biology (Edited by: Ulrike Gerischer). Caister Academic Press, U.K. (2008)


The beta-ketoadipate pathway is responsible for the degradation of aromatic compounds in Acinetobacter baylyi. To support the catabolism of multiple different substrates, a number of funneling pathways exist. In all cases, the respective genes form clusters and are expressed in operons under the control of specific regulator proteins. These generally recognize the respective aromatic substrate and/or degradation metabolite and bring about an increase in gene expression to provide the necessary set of enzymes. In addition to the specific induction mechanisms exist resulting in a repression of gene expression (despite the continued presence of the aromatic substrate). They respond to the simultaneous presence of other substrates which then are degraded with first priority. These findings indicate that many more genes than known up to now underlie such additional repressing mechanims allowing a more defined gene expression under conditions which are not only defined by one compound but by conditions of multiple carbon sources - a situation probably much closer to the real situation in the environment than a single substrate situation read more ...
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