Deletion of the aconitase gene in Corynebacterium glutamicum causes strong selection pressure for secondary mutations inactivating citrate synthase.

ABSTRACT: The aconitase gene acn of Corynebacterium glutamicum is regulated by four transcriptional regulators, indicating that the synthesis of this enzyme is carefully controlled. To understand the causes for this elaborate regulation, the properties of the Δacn-1 deletion mutant were analyzed in detail. The mutant was glutamate auxotrophic in glucose minimal medium, showed a strong growth defect, and secreted large amounts of acetate. None of these phenotypes could be complemented by plasmid-encoded aconitase, suggesting the presence of a secondary mutation. In fact, a point mutation within the gltA gene encoding citrate synthase was identified that caused the instability of the protein and an almost complete lack of its enzymatic activity. Subsequently, 27 further, independent Δacn clones were i

SUBMITTER: Baumgart M 

PROVIDER: S-EPMC3232852 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature