1knk

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Template:STRUCTURE 1knk

Crystal Structure of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate Synthase (ispF) from E. coli involved in Mevalonate-Independent Isoprenoid Biosynthesis

Overview

The enzyme 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MECDP) synthase catalyzes the conversion of 4-diphosphocytidyl-2-C-methyl-D-erythritol 2-phosphate (CDP-ME2P) to MECDP, a highly unusual cyclodiphosphate-containing intermediate on the mevalonate-independent pathway to isopentenyl diphosphate and dimethylallyl diphosphate. We now report two x-ray crystal structures of MECDP synthase refined to 2.8-A resolution. The first structure contains a bound Mn(2+) cation, and the second structure contains CMP, MECDP, and Mn(2+). The protein adopts a homotrimeric quaternary structure built around a central hydrophobic cavity and three externally facing active sites. Each of these active sites is located between two adjacent monomers. A tetrahedrally arranged transition metal binding site, potentially occupied by Mn(2+), sits at the base of the active site cleft. A phosphate oxygen of MECDP and the side chains of Asp(8), His(10), and His(42) occupy the metal ion coordination sphere. These structures reveal for the first time the structural determinants underlying substrate, product, and Mn(2+) recognition and the likely catalytic mechanism accompanying the biosynthesis of the cyclodiphosphate-containing isoprenoid precursor, MECDP.

About this Structure

1KNK is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

Reference

Structure and mechanism of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase. An enzyme in the mevalonate-independent isoprenoid biosynthetic pathway., Richard SB, Ferrer JL, Bowman ME, Lillo AM, Tetzlaff CN, Cane DE, Noel JP, J Biol Chem. 2002 Mar 8;277(10):8667-72. Epub 2002 Jan 10. PMID:11786530 Page seeded by OCA on Fri May 2 22:57:05 2008