2-C-methyl-D-erythritol 2,4-cyclopyrophosphate

2-C-methyl-D-erythritol 2,4-cyclopyrophosphate (MEcPP) is an intermediate compound in the methylerythritol phosphate pathway (MEP pathway), which is a crucial metabolic pathway for the biosynthesis of isoprenoids in bacteria, algae, and plants. This pathway is an alternative to the mevalonate pathway found in animals and some fungi.

Structure and Properties

MEcPP is a cyclic diphosphate ester of 2-C-methyl-D-erythritol. It is characterized by its cyclopyrophosphate group, which is a unique feature distinguishing it from other intermediates in the MEP pathway. The molecular formula of MEcPP is C₅H₁₂O₁₁P₂, and it has a molar mass of 310.09 g/mol.

Biosynthesis

MEcPP is synthesized from 4-diphosphocytidyl-2-C-methyl-D-erythritol 2-phosphate (CDP-ME2P) through the action of the enzyme MEcPP synthase (IspF). This reaction involves the cyclization of the diphosphate group, forming the characteristic cyclopyrophosphate ring.

Function in the MEP Pathway

In the MEP pathway, MEcPP serves as a precursor to 4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP), which is the immediate precursor to the universal isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The conversion of MEcPP to HMBPP is catalyzed by the enzyme HMBPP synthase (IspG).

Biological Significance

The MEP pathway, and by extension MEcPP, is essential for the production of isoprenoids, which are vital for various biological functions, including the synthesis of chlorophyll, carotenoids, hormones, and quinones. Inhibitors of the MEP pathway are of interest as potential antibiotics and herbicides due to the absence of this pathway in mammals.

Research and Applications

Research into MEcPP and the MEP pathway has implications for biotechnology and medicine. Understanding this pathway can lead to the development of new antimicrobial agents and the engineering of plants and microorganisms for enhanced production of valuable isoprenoids.

Also see

• Methylerythritol phosphate pathway
• Isoprenoid
• Mevalonate pathway
• HMBPP synthase
• Isopentenyl diphosphate