Send to

Choose Destination
J Bacteriol. 2018 Apr 9;200(9). pii: e00040-18. doi: 10.1128/JB.00040-18. Print 2018 May 1.

Increased Activity of Cystathionine β-Lyase Suppresses 2-Aminoacrylate Stress in Salmonella enterica.

Author information

Department of Microbiology, University of Georgia, Athens, Georgia, USA.
Department of Microbiology, University of Georgia, Athens, Georgia, USA


Reactive enamine stress caused by intracellular 2-aminoacrylate accumulation leads to pleiotropic growth defects in a variety of organisms. Members of the well-conserved RidA/YER057c/UK114 protein family prevent enamine stress by enhancing the breakdown of 2-aminoacrylate to pyruvate. In Salmonella enterica, disruption of RidA allows 2-aminoacrylate to accumulate and to inactivate a variety of pyridoxal 5'-phosphate-dependent enzymes by generating covalent bonds with the enzyme and/or cofactor. This study was initiated to identify mechanisms that can overcome 2-aminoacrylate stress in the absence of RidA. Multicopy suppressor analysis revealed that overproduction of the methionine biosynthesis enzyme cystathionine β-lyase (MetC) (EC alleviated the pleiotropic consequences of 2-aminoacrylate stress in a ridA mutant strain. Degradation of cystathionine by MetC was not required for suppression of ridA phenotypes. The data support a model in which MetC acts on a noncystathionine substrate to generate a metabolite that reduces 2-aminoacrylate levels, representing a nonenzymatic mechanism of 2-aminoacrylate depletion.IMPORTANCE RidA proteins are broadly conserved and have been demonstrated to deaminate 2-aminoacrylate and other enamines. 2-Aminoacrylate is generated as an obligatory intermediate in several pyridoxal 5'-phosphate-dependent reactions; if it accumulates, it damages cellular enzymes. This study identified a novel mechanism to eliminate 2-aminoacrylate stress that required the overproduction, but not the canonical activity, of cystathionine β-lyase. The data suggest that a metabolite-metabolite interaction is responsible for quenching 2-aminoacrylate, and they emphasize the need for emerging technologies to probe metabolism in vivo.


2-aminoacrylate; RidA; cystathionine β-lyase; endogenous stress

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center