The Pur10 protein encoded in the gene cluster for puromycin biosynthesis of Streptomyces alboniger is an NAD‐dependent ATP dehydrogenase

Abstract

<jats:p>The <jats:italic>pur10</jats:italic> gene of the puromycin (<jats:italic>pur</jats:italic>) cluster of <jats:italic>Streptomyces alboniger</jats:italic> is essential for the biosynthesis of this antibiotic. Highly purified Pur10 protein, obtained in <jats:italic>Escherichia coli</jats:italic> as a recombinant protein fused to a histidine tail, had an NAD‐dependent ATP dehydrogenase activity. The <jats:italic>K</jats:italic> <jats:sub>m</jats:sub> and <jats:italic>V</jats:italic> <jats:sub>max</jats:sub> values for ATP were 0.49 mM and 14.5 nmol/min and for NAD 0.53 mM and 15.2 nmol/min, respectively. The ATP‐derived product of the reaction apparently decomposed producing a triphosphorylated compound plus an adenine derivative. These and previous results suggested that Pur10 carries out the first step of the puromycin biosynthetic pathway, namely, conversion of ATP into 3′‐keto‐3′‐deoxyATP.