Leucyl/phenylalanyl (L/F)-tRNA-protein transferase-mediated N-terminal specific labelling of a protein in vitro.

Abstract

N-terminal specific radioisotope (RI) labelling of a protein posessing lysine as the N-terminal residue (Lys-XBD) was achieved under mild enzymatic reaction condition using L/F-tRNA-protein transferase. To expose a single lysine moiety only at the N-teminal site, we overexpressed pelB signal peptide-Lys-XBD fusion protein using the bacterial expression host BL21(DE3). The pelB signal peptide was sponteneously cleaved in E. coli to obtain the desired Lys-XBD.