InterPro domain: IPR017178

This entry includes 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate synthase, which converts 2C-methyl-D-erythritol 2,4-cyclodiphosphate (ME-2,4CPP) into 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate in the sixth step of nonmevalonate terpenoid biosynthesis. It is essential in Escherichia coli. The enzyme is described as "atypical" because it contains a partially-duplicated domain. The family is found in bacteria, where it is widely but not universally distributed, and chloroplasts, where it is essential for chloroplast development [ 1 ], salicylic acid-mediated disease resistance to pathogens [ 2 ] and requires ferrdoxin as a co-factor [ 3 ]. No homology can be detected between this family and other proteins.

1. CHLOROPLAST BIOGENESIS genes act cell and noncell autonomously in early chloroplast development. Plant Physiol. 135, 471-82
2. The Arabidopsis csb3 mutant reveals a regulatory link between salicylic acid-mediated disease resistance and the methyl-erythritol 4-phosphate pathway. Plant J. 44, 155-66
3. Isoprenoid biosynthesis in chloroplasts via the methylerythritol phosphate pathway: the (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (GcpE) from Arabidopsis thaliana is a [4Fe-4S] protein. J. Biol. Inorg. Chem. 10, 131-7