SUBSTRATE SPECIFICITY OF tRNA-DEPENDENT AMIDE-FORMING ENZYME

摘要

Streptothricins (STs) produced by Streptomyces strains are broad-spectrum antibiotics and are characterized by a streptothrisamine core structure with the L-β-lysine (β-Lys) residue and its oligomeric side chains [oligo(β-Lys)]. In addition to the STs, Streptomyces strains has been known to produce ST-related compounds, BD-12, citromycin, glycinothricin, etc., which possess a glycine-derived side chain rather than the β-Lys residue. We have reported that the amide bonds connecting the amino-acid side chains in ST and BD-12 are formed via NRPS (1) and tRNA-dependent (2) pathways, respectively . Here, we report that a tRNA-dependent amide bond-forming enzyme found by genome mining showed a broad substrate specificity, and generation of new compounds using unnatural aminoacyl-tRNAs as substrates will be presented.