2026-10-03T00:37:10Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/121482026-09-26T00:05:32Zcom_10259_4862com_10259_5086com_10259_2604col_10259_4863

Characterization of the polyene macrolide P450 epoxidase from Streptomyces natalensis that converts de-epoxypimaricin into pimaricin Mendes, Marta V. Antón Fidalgo, Nuria Martín, Juan F. Aparicio, Jesús F. Cytochrome P450 mono-oxygenase Epoxidase Pimaricin Polyene Polyketide synthase The biosynthesis of the antifungal agent pimaricin by Streptomyces natalensis has been proposed to involve a cytochrome P450 encoded by the gene pimD. Pimaricin is derived from its immediate precursor de-epoxypimaricin by epoxidation of the C-4–C-5 double bond on the macrolactone ring. We have overproduced PimD with a N-terminal His6 affinity tag in Escherichia coli and purified the enzyme for kinetic analysis. The protein showed a reduced CO-difference spectrum with a Soret maximum at 450 nm, indicating that it is a cytochrome P450. Purified PimD was shown to catalyse the in vitro C-4–C-5 epoxidation of 4,5-de-epoxypimaricin to pimaricin. The enzyme was dependent on NADPH for activity with optimal pH at 7.5, and the temperature optimum was 30 °C. The kcat value for the epoxidation of de-epoxypimaricin was similar to the values reported for other macrolide oxidases. Enzyme activity was inhibited at high substrate concentration. This is the first time that a polyene macrolide P450 mono-oxygenase has been expressed heterologously and studied. The unique specificity of this epoxidase should be useful for the oxidative modification of novel polyene macrolide antibiotics. 2026-09-25T09:40:17Z 2026-09-25T09:40:17Z 2005 info:eu-repo/semantics/article 0264-6021 https://hdl.handle.net/10259/12148 10.1042/BJ20040490 1470-8728 eng Biochemical journal. 2005, V. 386, n. 1, p. 57-62 https://doi.org/10.1042/BJ20040490 info:eu-repo/semantics/openAccess Biochemical society