Cloning and expression of a gene encoding N-glycosyltrasferase (ngt) from Saccharothrix aerocolonigenes ATCC39243

In the course of our bioconversion studies on the derivatives of an indoloc arbazole, J-104303, Saccharothrix aerocolonigenes ATCC39243 was found to co nvert J-104303, which was added into the culture medium, to its glycosylate d derivative, J-109384. In order to clone the gene having the ability to co nvert J-104303 to J-109384, a library of Saccharothrix aerocolonigenes ATCC 39243 DNA fragments was constructed using Streptomyces lividans TK21 and pI J702 as host strain and vector, respectively. By examining more than 5,000 transformants, one was found to convert J-104303 to J-109384. Sequence anal ysis of the inserted DNA fragment revealed an open reading frame with 1,245 base pairs, named ngt. The transformant containing this ngt gene was also found to introduce a D-glucose moiety into 6-N-methylarcyriaflavin C. Furth ermore, when ngt was introduced into Streptomyces mobaraensis BA13793, a pr oducer of J-104303, the resulting transformant produced J-109384 directly.