A potent seryl tRNA synthetase inhibitor SB-217452 isolated from a Streptomyces species.

A potent inhibitor of seryl tRNA synthetase, designated SB-217452 has been isolated from Streptomyces sp. ATCC 700974. The fermentation, isolation, structure elucidation and some properties are described. SB-217452 showed inhibitory activity against both Staphylococcus aureus and rat seryl tRNA synthetases, with similar IC50 values of approximately 8nM. The inhibitor is the serine linked nucleoside moiety of the antibiotic albomycin δ2. In contrast to albomycin δ2, SB-217452 showed only very weak antibacterial activity against a limited range of microorganisms. The compound has not been previously reported as a naturally occurring metabolite. In addition to SB-217452, albomycin δ2 Fe3+ complex and the novel Al3+ complex were isolated from the fermentation. These complexes had no seryl tRNA synthetase inhibitory activity.