Flavin-dependent halogenases: Nature's major tool for the formation of halogenated compounds

Speaker: Prof. Dr. Karl-Heinz van Pée (Biochemistry, Technical University Dresden, Germany)

Organisator Laboratory of Biochemistry

vr 10 maart 2017 10:00

Locatie Helix, gebouwnummer 124
Stippeneng 4
6708 WE Wageningen
Zaal/kamer 1100
For a long time haloperoxidases and perhydrolases were considered the only types of enzymes catalysing the incorporation of halogen atoms into organic compounds. Haloperoxidases produce hypohalous acid which then reacts with electron-rich compounds to form halogenated products in a non-enxymatic reaction. Thus their involvement in the biosynthesis of complex halogenated metabolites can only be very limited. During the investigation of the biosynthetic pathway of the antifungal antibiotic pyrrolnitrin, an enzyme was found to catalyse the regioselective chlorination of tryotophan to 7-chlorotryptophan. This tryptophan 7-halogenase (PrnA) requires FADH2 which is supplied by a flavin reductase. Determination of the 3D-structure allowed the elucidation of the reaction mechanism of PrnA. Comparison with tryptophan 5-halogenase (PyrH) showed how regioselective halogenation is accomplished.