Oxidative Alkene Cleavage Catalysed by Manganese-Dependent Cupin TM1459 from Thermotoga maritima

Abstract

A novel biocatalytic oxidative alkene cleavage activity was identified in protein TM1459 from Thermotoga maritima, a so far uncharacterised metalloprotein with a cupin fold, which preferentially binds manganese (over iron and zinc). Various styrene derivatives were converted with high chemoselectivity to the corresponding carbonyl compounds by the manganese-containing protein, using organic hydroperoxide and molecular oxygen as oxidant. 4-Chloroacetophenone could be obtained in 40% conversion from 4-chloro-α-methylstyrene (50 mM) in a biphasic system using ethyl acetate as organic cosolvent (5% v/v), while 76% conversion was obtained at a lower substrate concentration (10 mM). This novel biocatalyst can be easily over-expressed in Escherichia coli in exceptionally high yield and purified, and thus may offer a valuable and safer alternative in oxidative C=C bond cleavage reactions for synthetic applications.