Structural and functional consequences of mutating a proteobacteria-specific surface residue in the catalytic domain of Escherichia coli GluRS

► Arg266 in Escherichia coli GluRS is critical for efficient glutamylation. ► Arg266 in E. coli GluRS is a proteobacterial signature. ► Strategy of tRNAGlu glutamylation is phylum-specific in bacteria.