A synthetic mutant tRNAiMet that can not be not be conjugated with a threonyl-carbamoyl moiety at position 37 to become N6-threonylcarbamoyl-adenosine. Carries nucleotide substitution A37G. Contains the transcriptional regulatory sequences, as well as the 5' and 3' regions of endogenous tRNA:iMet-CAT-1-3.