5fpp | pdb_00005fpp

Structure of a pre-reaction ternary complex between sarin- acetylcholinesterase and HI-6

spinqualitylabelsall models 5fpp, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5fpp is a 2 chain structure with sequence from Lk3 transgenic mice. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AE3, CO3, HI6, NAG, P6G NonStd Res: SGB Related: 5foq, 5fpq Activity: Acetylcholinesterase, with EC number 3.1.1.7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ACES_MOUSE] Terminates signal transduction at the neuromuscular junction by rapid hydrolysis of the acetylcholine released into the synaptic cleft. Publication Abstract from PubMed Organophosphorus nerve agents interfere with cholinergic signaling by covalently binding to the active site of the enzyme acetylcholinesterase (AChE). This inhibition causes an accumulation of the neurotransmitter acetylcholine, potentially leading to overstimulation of the nervous system and death. Current treatments include the use of antidotes that promote the release of functional AChE by an unknown reactivation mechanism. We have used diffusion trap cryocrystallography and density functional theory (DFT) calculations to determine and analyze prereaction conformers of the nerve agent antidote HI-6 in complex with Mus musculus AChE covalently inhibited by the nerve agent sarin. These analyses reveal previously unknown conformations of the system and suggest that the cleavage of the covalent enzyme-sarin bond is preceded by a conformational change in the sarin adduct itself. Together with data from the reactivation kinetics, this alternate conformation suggests a key interaction between Glu202 and the O-isopropyl moiety of sarin. Moreover, solvent kinetic isotope effect experiments using deuterium oxide reveal that the reactivation mechanism features an isotope-sensitive step. These findings provide insights into the reactivation mechanism and provide a starting point for the development of improved antidotes. The work also illustrates how DFT calculations can guide the interpretation, analysis, and validation of crystallographic data for challenging reactive systems with complex conformational dynamics. Structure of a prereaction complex between the nerve agent sarin, its biological target acetylcholinesterase, and the antidote HI-6.,Allgardsson A, Berg L, Akfur C, Hornberg A, Worek F, Linusson A, Ekstrom FJ Proc Natl Acad Sci U S A. 2016 May 2. pii: 201523362. PMID:27140636 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Acetylcholinesterase 3D structures

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