An Engineered E. coli Strain for Direct in Vivo Fluorination

Abstract

Selectively fluorinated compounds are found frequently in pharmaceutical and agrochemical products where currently 25￢ﾀﾓ30￢ﾀﾉ% of optimised compounds emerge from development containing at least one fluorine atom. There are many methods for the site￢ﾀﾐspecific introduction of fluorine, but all are chemical and they often use environmentally challenging reagents. Biochemical processes for C￢ﾈﾒF bond formation are attractive, but they are extremely rare. In this work, the fluorinase enzyme, originally identified from the actinomycete bacterium Streptomyces cattleya, is engineered into Escherichia coli in such a manner that the organism is able to produce 5￢ﾀﾲ￢ﾀﾐfluorodeoxyadenosine (5￢ﾀﾲ￢ﾀﾐFDA) from S￢ﾀﾐadenosyl￢ﾀﾐl￢ﾀﾐmethionine (SAM) and fluoride in live E.￢ﾀﾅcoli cells. Success required the introduction of a SAM transporter and deletion of the endogenous fluoride efflux capacity in order to generate an E.￢ﾀﾅcoli host that has the potential for future engineering of more elaborate fluorometabolites.