3KEL

Crystal Structure of IspH:PP complex

3KEL の概要

• エントリーDOI: 10.2210/pdb3kel/pdb
• 関連するPDBエントリー: 3DNF 3F7T 3KE8 3KE9 3KEF 3KEM
• 分子名称: 4-hydroxy-3-methylbut-2-enyl diphosphate reductase, FE3-S4 CLUSTER, PYROPHOSPHATE 2-, ... (4 entities in total)
• 機能のキーワード: isph, lytb, iron-sulfure protein, malaria, tuberculosis, non-mevalonic acid pathway, iron, iron-sulfur, isoprene biosynthesis, metal-binding, nadp, oxidoreductase
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 73101.31

構造登録者

Groll, M.,Graewert, T.,Span, I.,Eisenreich, W.,Bacher, A. (登録日: 2009-10-26, 公開日: 2010-01-12, 最終更新日: 2023-11-01)

主引用文献

Grawert, T.,Span, I.,Eisenreich, W.,Rohdich, F.,Eppinger, J.,Bacher, A.,Groll, M.
Probing the reaction mechanism of IspH protein by x-ray structure analysis.
Proc.Natl.Acad.Sci.USA, 107:1077-1081, 2010

PubMed Abstract: Isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) represent the two central intermediates in the biosynthesis of isoprenoids. The recently discovered deoxyxylulose 5-phosphate pathway generates a mixture of IPP and DMAPP in its final step by reductive dehydroxylation of 1-hydroxy-2-methyl-2-butenyl 4-diphosphate. This conversion is catalyzed by IspH protein comprising a central iron-sulfur cluster as electron transfer cofactor in the active site. The five crystal structures of IspH in complex with substrate, converted substrate, products and PP(i) reported in this article provide unique insights into the mechanism of this enzyme. While IspH protein crystallizes with substrate bound to a [4Fe-4S] cluster, crystals of IspH in complex with IPP, DMAPP or inorganic pyrophosphate feature [3Fe-4S] clusters. The IspH:substrate complex reveals a hairpin conformation of the ligand with the C(1) hydroxyl group coordinated to the unique site in a [4Fe-4S] cluster of aconitase type. The resulting alkoxide complex is coupled to a hydrogen-bonding network, which serves as proton reservoir via a Thr167 proton relay. Prolonged x-ray irradiation leads to cleavage of the C(1)-O bond (initiated by reducing photo electrons). The data suggest a reaction mechanism involving a combination of Lewis-acid activation and proton coupled electron transfer. The resulting allyl radical intermediate can acquire a second electron via the iron-sulfur cluster. The reaction may be terminated by the transfer of a proton from the beta-phosphate of the substrate to C(1) (affording DMAPP) or C(3) (affording IPP).

PubMed: 20080550
DOI: 10.1073/pnas.0913045107

実験手法

X-RAY DIFFRACTION (1.8 Å)