This protein of previously unknown biochemical function has now been identified as an enzyme of the non-mevalonate pathway of IPP biosynthesis. Chlamydial members of the family have a long insert. The family is largely restricted to Bacteria, where it is widely but not universally distributed. No homology can be detected between the GcpE family and other proteins. [Biosynthesis of cofactors, prosthetic groups, and carriers, Other]