Nobutaka Oohata

Cloning and expression of the FR901379 acylase gene from Streptomyces sp. no. 6907

FR901379 acylase, an enzyme that catalyzes the hydrolysis of the palmitoyl moiety of the antifungal lipopeptide FR901379, was purified from the culture broth of Streptomyces sp. no. 6907 (FERM BP-5809), revealing the 80 kDa, two-subunit heterodimeric protein characteristic of the β-lactam acylase family. Using oligodeoxyribonucleotide primers constructed on the basis of the N-terminal amino acid sequence of each purified subunit, the gene was identified from a cosmid library of Streptomyces sp. no. 6907 DNA. The deduced 775 amino acid sequence corresponded to a single polypeptide chain containing two subunits, and it shared 41.7% identity with aculeacin A acylase from Actinoplanes utahensis NRRL12052. FR901379 acylase activity was found to be 250-fold higher in the recombinant Streptomyces lividans 1326 carrying the cloned gene than in the original Streptomyces sp. no. 6907 strain.

Screening and characterization of microorganisms with FR901379 acylase activity

A simple and rapid screen was performed for microorganisms producing cyclic lipopeptide acylase, an enzyme that deacylates the acyl side chain of FR901379 to yield a cyclic peptide, FR179642, which is an important intermediate in producing micafungin. Among ∼3800 newly isolated strains from soil samples, 5 microorganisms expressing high acylase activity were selected and classified, 3 as Streptomyces spp. and 2 as filamentous fungi. This is the first time that these strains have been identified as cyclic lipopeptide acylase producers. Both fungi and streptomycetes showed differing optimum pH and temperature profiles for acylase activity.