Antimicrobial resistance is a critical global health issue. Bacteria evade drugs by tightly controlling when, how much and how accurately proteins are made, using mechanisms such as drug efflux, drug‑degrading enzymes or altered targets. Transfer RNA (tRNA) molecules act as molecular carriers that attach chemical “stickers” to modulate translation under metabolic or oxidative stress.
In a recent open‑access paper, researchers identified the first pyridoxal‑phosphate (PLP)‑dependent tRNA‑modifying enzyme, aminovaleramididine synthetase (AvaS). AvaS converts the known modification lysidine (k2C) into aminovaleramide cytidine (ava2C), establishing a direct link between PLP enzymes and tRNA chemistry.
Using SMART AMR’s high‑throughput LC‑MS/MS RNA‑modification profiling platform, thousands of Pseudomonas aeruginosa mutants were screened, leading to the discovery of AvaS. ava2C was also detected in Acinetobacter baumannii, Vibrio cholerae and the plant Arabidopsis thaliana, indicating a broad biological distribution.
AvaS employs the vitamin B6 derivative PLP as a cofactor, expanding the known repertoire of tRNA‑modifying mechanisms—previously limited to methylation, thiolation and isomerisation—to include PLP‑dependent chemistry. Functional assays showed that ava2C alters codon reading, accelerating and sharpening protein synthesis, thereby aiding bacterial adaptation to metabolic and oxidative stress.
The study highlights the power of SMART AMR’s epitranscriptomics platform for large‑scale discovery of unknown RNA‑modifying enzymes, offering new avenues for drug‑target identification and antimicrobial strategy development. Future work will dissect how ava2C influences bacterial stress responses and explore whether similar modifications operate in other organisms.
Review