A novel halogenase gene from the pentachloropseudilin producer Actinoplanes sp. ATCC 33002 and detection of in vitro halogenase activity

Abstract

A novel halogenase gene (halB) was isolated from a cosmid library of the pentachloropseudilin producer Actinoplanes sp. ATCC 33002. The halogenase has high identity (55%) to the flavin-dependent monodechloroaminopyrrolnitrin-3 halogenase from pyrrolnitrin biosynthesis and to the halogenases PltM and PltA (35% and 28%, respectively) involved in pyoluteorin biosynthesis. The enzyme has no sequence similarity to the flavin-dependent tryptophan halogenases. The gene could be heterologously expressed in Pseudomonas aureofaciens ACN as soluble protein. Chlorinating activity of HalB was shown with two synthetic substrates with structural similarity to pentachloropseudilin. HalB is the first halogenase from an actinomycete and only the third halogenase for which halogenating activity could be demonstrated in vitro.