Rayamajhi_2020_Biotechnol.Bioprocess.Eng_25_414

Nodusmicin and 18-O-acetyl-nodusmicin were isolated as a co-metabolite of nargenicin from Nocardia sp. CS682. NgnL belonging to the alpha/beta-hydrolase superfamily was heterologously expressed in Escherichia coli BL21 and was evaluated for its potential for acetylation of nodusmicin by in-vitro reactions. The generation of 18-O-acetyl nodusmicin was confirmed by high resolution-quadruple time of flight mass spectrometry (HR-QTOF-MS). Thus, it was concluded that NgnL can perform regiospecific acetylation of nodusmicin at 18-OH in presence of acetyl-CoA as an acetate donor. The enzyme kinetic parameters as Km and Vmax of the enzymes were also evaluated. Further, the biosynthetic role of the enzyme for acetylation of nodusmicin was confirmed by gene inactivation and complementation studies. Hence, from this study, it was established that NgnL is regiospecific acetyltransferase involved in the biosynthesis of 18-O-acetyl nodusmicin in Nocardia sp. CS682