Tetrocarcins N and O, glycosidic spirotetronates from a marine-derived Micromonospora sp. identified by PCR-based screening

Abstract

Two new glycosidic spirotetronate antibiotics, tetrocarcins N (1) and O (2), were isolated and identified from the marine-derived Micromonospora sp. 5-297 using a PCR-based genetic screening method targeting the dTDP-glucose-4,6-dehydratase gene. Their structures were determined by extensive IR, NMR, and MS spectroscopic analyses. Tetrocarcin O (2) is a derivative of 1 that lacks the terminal L-amicetose moiety at C-9. Compound 1 and 2 exhibited antibacterial activity against Bacillus subtilis with MIC values of 2 and 64 μg mL⁻¹, respectivly. It seems that the sugar moieties at C-9 and the formyl group at C-32 play important roles in the antibacterial activity of the tetrocarcins.