Structure of the E-1-hydroxy-2-methyl-but-2-enyl-4-diphosphate synthase (GcpE) from Thermus thermophilus.

Isoprenoids are biosynthesized via the mevalonate or the 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways the latter being used by most pathogenic bacteria, some parasitic protozoa, plant plastids, but not by animals. We determined the X-ray structure of the homodimeric [4Fe-4S] cluster carrying E-1-hydroxy-2-methyl-but-2-enyl-4-diphosphate synthase (GcpE) of Thermus thermophilus which catalyzes the penultimate reaction of the MEP pathway and is therefore an attractive target for drug development. The [4Fe-4S] cluster ligated to three cysteines and one glutamate is encapsulated at the intersubunit interface. The substrate binding site lies in front of an (αβ)(8) barrel. The great [4Fe-4S] cluster-substrate distance implicates large-scale domain rearrangements during the reaction cycle.