4ITN

Crystal structure of "compact P-loop" LpxK from Aquifex aeolicus in complex with chloride at 2.2 angstrom resolution

4ITN の概要

• エントリーDOI: 10.2210/pdb4itn/pdb
• 関連するPDBエントリー: 4EHW 4EHX 4EHY
• 分子名称: Tetraacyldisaccharide 4'-kinase, GLYCEROL, 4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID, ... (5 entities in total)
• 機能のキーワード: membrane protein, kinase, lipid a, p-loop, p-loop containing nucleoside triphosphate hydrolase, disaccharide-1-phosphate 4'-kinase, membrane, transferase, lipid metabolism, tetraacyldisaccharide 4'-kinase
• 由来する生物種: Aquifex aeolicus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 37239.86

構造登録者

Emptage, R.P.,Pemble IV, C.W.,York, J.D.,Raetz, C.R.H.,Zhou, P. (登録日: 2013-01-18, 公開日: 2013-04-03, 最終更新日: 2023-09-20)

主引用文献

Emptage, R.P.,Pemble, C.W.,York, J.D.,Raetz, C.R.,Zhou, P.
Mechanistic Characterization of the Tetraacyldisaccharide-1-phosphate 4'-Kinase LpxK Involved in Lipid A Biosynthesis.
Biochemistry, 52:2280-2290, 2013

PubMed Abstract: The sixth step in the lipid A biosynthetic pathway involves phosphorylation of the tetraacyldisaccharide-1-phosphate (DSMP) intermediate by the cytosol-facing inner membrane kinase LpxK, a member of the P-loop-containing nucleoside triphosphate (NTP) hydrolase superfamily. We report the kinetic characterization of LpxK from Aquifex aeolicus and the crystal structures of LpxK in complex with ATP in a precatalytic binding state, the ATP analogue AMP-PCP in the closed catalytically competent conformation, and a chloride anion revealing an inhibitory conformation of the nucleotide-binding P-loop. We demonstrate that LpxK activity in vitro requires the presence of a detergent micelle and formation of a ternary LpxK-ATP/Mg(2+)-DSMP complex. Using steady-state kinetics, we have identified crucial active site residues, leading to the proposal that the interaction of D99 with H261 acts to increase the pKa of the imidazole moiety, which in turn serves as the catalytic base to deprotonate the 4'-hydroxyl of the DSMP substrate. The fact that an analogous mechanism has not yet been observed for other P-loop kinases highlights LpxK as a distinct member of the P-loop kinase family, a notion that is also reflected through its localization at the membrane, lipid substrate, and overall structure.

PubMed: 23464738
DOI: 10.1021/bi400097z

実験手法

X-RAY DIFFRACTION (2.1912 Å)