RidA Proteins Protect against Metabolic Damage by Reactive Intermediates

Area of Science:

• Biochemistry
• Molecular Biology
• Metabolic Engineering

Background:

• The Rid (YjgF/YER057c/UK114) protein superfamily is conserved across all domains of life.
• Rid family members have been linked to diverse cellular processes, including amino acid biosynthesis and carcinogenesis.
• Despite numerous studies and available structures, the biochemical function of RidA enzymes remained elusive for decades.

Purpose of the Study:

• To elucidate the biochemical function of the RidA protein.
• To establish the physiological framework for the RidA paradigm in *Salmonella enterica*.
• To explore the conserved function of RidA and its implications across different organisms.

Main Methods:

• Sequence homology analysis to define the Rid protein superfamily.
• Bacterial model system (*Salmonella enterica*) to investigate RidA function.
• Metabolite analysis to identify accumulated reactive intermediates in *ridA* mutants.

Main Results:

• The function of RidA was elucidated by linking *ridA* mutant phenotypes to the accumulation of 2-aminoacrylate (2AA).
• 2AA was identified as a reactive metabolite that damages metabolic enzymes.
• Conserved enamine/imine deaminase activity suggests 2AA accumulation is a common consequence of RidA absence.

Conclusions:

• The RidA paradigm explains enamine stress due to 2AA accumulation, impacting metabolic enzymes.
• Differences in metabolic network architecture contribute to diverse phenotypes observed in various organisms.
• Understanding RidA function provides insights into metabolic network evolution and diversity.