Structural Prediction and Functional Mechanistic Characterization of Farnesyl Diphosphate Synthase from Mycobacterium tuberculosis.

Tuberculosis, triggered by the bacterium Mycobacterium tuberculosis (Mtb), continues to pose a major global health challenge, further intensified by the rise in drug resistance. The enzyme (2E,6E)-farnesyl diphosphate synthase (FPPS) in Mtb catalyzes the synthesis of farnesyl diphosphate (FPP), which is crucial for processes such as arabinogalactan biosynthesis in the cell wall. However, the functional characterization of Mtb FPPS is not well understood. Here, a hydrodynamic radius of 5.4 ± 0.3 nm was obtained for monomeric FPPS. The molecular docking relied on a structure predicted using AlphaFold2, and site-specific mutagenesis was subsequently executed. Mutants K201A or K266A showed significantly reduced activity, while D112A, D116A, or R121A mutations completely abolished activity. Deletion of specific segments (Δ58-74, Δ117-126, or Δ249-268) also resulted in complete loss of activity. This work lays a crucial foundation for advancing innovative tuberculosis therapies that function via an alternative mechanistic pathway.