The identification of isoprenoids that bind in the intersubunit cavity of Escherichia coli 2C-methyl-D-erythritol-2,4-cyclodiphosphate synthase by complementary biophysical methods.
The discovery of a distinct metabolic pathway, the non-mevalonate or 1-deoxy-D-xylulose-5-phosphate (DOXP) pathway for isoprenoid precursor biosynthesis, in eubacteria and apicomplexan parasites has revealed a new set of potential drug targets. The emphasis of research on this pathway has been on delineating the intermediates and the biochemical and structural characterization of component enzymes. Two new monoclinic crystal forms of recombinant Escherichia coli 2C-methyl-D-erythritol-2,4-cyclodiphosphate (MECP) synthase cocrystallized with (i) CMP and (ii) CMP and MECP show well defined electron density at the subunit interface suggestive of an isoprenoid-like ligand. 31P NMR analysis of the recombinant protein sample indicates the presence of bound diphosphate species and electrospray mass spectrometry identifies a mixture of isopentenyl diphosphate (and/or dimethylallyl diphosphate), geranyl diphosphate and farnesyl diphosphate in an approximate ratio of 1:4:2. The most prevalent species, geranyl diphosphate, was successfully modelled into the electron density, revealing the important protein-ligand interactions that stabilize binding of the isoprenoid. The observation that MECP synthase binds three metabolites that are produced by enzymes two, three and four stages downstream in isoprenoid biosynthesis suggests that feedback regulation of the non-mevalonate pathway is possible.
Kemp
Lauris E
LE
Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland.
Alphey
Magnus S
MS
Bond
Charles S
CS
Ferguson
Michael A J
MA
Hecht
Stefan
S
Bacher
Adelbert
A
Eisenreich
Wolfgang
W
Rohdich
Felix
F
Hunter
William N
WN
D001665:Binding Sites; D018360:Crystallography, X-Ray; D019992:Databases as Topic; D004583:Electrons; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D007477:Ions; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D010710:Phosphates / Q000737:chemistry; D019761:Phosphorus-Oxygen Lyases / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013729:Terpenes / Q000737:chemistry*; D015032:Zinc
D029968:Escherichia coli Proteins; D007477:Ions; D008024:Ligands; D010710:Phosphates; D011506:Proteins; D011994:Recombinant Proteins; D013729:Terpenes; D019761:Phosphorus-Oxygen Lyases; C400181:ISPF protein, E coli; D015032:Zinc