Bacterial enzyme evolution fine-tunes protein synthesis speed

Researchers have identified evolutionary changes in the enzyme isoleucyl-tRNA synthetase (IleRS) that may allow bacteria to fine-tune protein synthesis speed, according to a study published in Nature Communications on October 12, 2026, by teams from Institute of Science Tokyo, the University of Zagreb, and ETH Zürich. The study traced IleRS evolution and found three distinct clades, including a newly recognized group called IleRS-A, revealing that C-terminal remodeling—such as repeated loss of the INS subdomain—can alter tRNA binding and increase catalytic turnover by up to fourfold without disrupting essential function. Mutations affecting anticodon recognition, however, proved critical for bacterial growth. The findings suggest bacteria have repeatedly streamlined parts of this essential enzyme, potentially enhancing aminoacylation rates and contributing to faster protein synthesis, while maintaining core catalytic function through structural flexibility.