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Attachment of protein affinity-labeling reagents of variable length and amino acid specificity to E. coli tRNAfMet.

Transamination with bifunctional amines in the presence of bisulfite has been used to attach side chains of variable length to the N4-position of single stranded cytidine residues in E. coli tRNAfMet. Such side chains, terminating in reactive primary amino groups, have been coupled to a variety of N-hydroxysuccinimide esters. The resulting modified tRNAs carry protein affinity labeling groups capable of covalent reaction with a variety of amino acids.