BaCas12a3 represents a new subtype of type V CRISPR effector with collateral activity toward tRNA.

BaCas12a3, a new type V CRISPR effector, specifically cleaves tRNA's 3' CCA end, causing growth arrest without DNA damage in host cells.

• Why it matters: Understanding diverse CRISPR mechanisms is crucial for developing precise gene editing tools and antiviral strategies, especially those that avoid damaging host DNA.
• What they did: Researchers characterized BaCas12a3 through plasmid interference, western blot, biochemical assays, cryo-EM structures, and mutagenesis, revealing its unique tRNA-cleaving activity.
• The result: This discovery broadens the functional scope of CRISPR effectors, enabling targeted tRNA cleavage that can inhibit growth without DNA damage, with potential biotechnological applications.