leptomycin b

Leptomycin B (LMB) is a potent inhibitor of the nuclear export of proteins and is a potent antifungal antibiotic blocking the eukaryotic cell cycle. Leptomycin B inactivates CRM1/exportin 1 by covalent modification at a cysteine residue.

Leptomycin A, a metabolite derived from Streptomyces, acts as an inhibitor of CRM1 (exportin 1) and effectively suppresses HIV-1 replication. Compared to Leptomycin B, it exhibits lesser potency. Leptomycin A hampers the interaction between CRM1 and nuclear export signals, effectively hindering the nuclear export of a wide array of proteins.

Anguinomycin A is an antibiotic first isolated from a Streptomyces sp. and analog of leptomycin B that is highly cytotoxic to mouse P388 leukemia cells in vitro (IC50 = 0.1-0.2 ng/ml). It also demonstrates antitumor activity at 62.5 μg/kg/day against Lewis lung carcinoma in mice.