Structures of Mycobacterium tuberculosis isoprenyl diphosphate synthase Rv2173 in substrate-bound forms

We report the structure of M. tuberculosis isoprenyl diphosphate synthase Rv2173 in three forms, including two with substrate (isoprenyl diphosphate and dimethylallyl diphosphate) occupying the allylic substrate site in different binding poses, with different numbers of metal ions bound. The homodimeric structures possess a canonical all-α-helical trans-isoprenyl diphosphate synthase fold, which supports small but significant differences, notably in the ordering of the C-terminus that closes the active site.