ATP-dependent agmatine transferase that catalyzes the formation of 2-agmatinylcytidine (agm2C) at the wobble position (C34) of tRNA(Ile2), converting the codon specificity from AUG to AUA. agmatine + ATP + cytidine(34) in tRNA(Ile2) + H2O = 2-agmatinylcytidine(34) in tRNA(Ile2) + AMP + 2 H(+) + 2 phosphate Belongs to the TiaS family. Extended N-terminus.