Lactate racemase is a nickel-dependent enzyme activated by a widespread maturation system

Racemases catalyse the inversion of stereochemistry in biological molecules, giving the organism the ability to use both isomers. Among them, lactate racemase remains unexplored due to its intrinsic instability and lack of molecular characterization. Here we determine the genetic basis of lactate racemization in Lactobacillus plantarum. We show that, unexpectedly, the racemase is a nickel-dependent enzyme with a novel α/β fold. In addition, we...