3zlv

Crystal structure of mouse acetylcholinesterase in complex with tabun and HI-6

spinqualitylabelsall models 3zlv, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3zlv is a 2 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.5Å Ligands: 1KA, CO3, HI6, PE4, SUN 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 Nerve agents such as tabun, cyclosarin and Russian VX inhibit the essential enzyme acetylcholinesterase (AChE) by organophosphorylating the catalytic serine residue. Nucleophiles, such as oximes, are used as antidotes as they can reactivate and restore the function of the inhibited enzyme. The oxime HI-6 shows a notably low activity on tabun adducts but can effectively reactivate adducts of cyclosarin and Russian VX. To examine the structural basis for the pronounced substrate specificity of HI-6, we determined the binary crystal structures of Mus musculus AChE (mAChE) conjugated by cyclosarin and Russian VX and found a conformational mobility of the side chains of Phe338 and His447. The interaction between HI-6 and tabun-adducts of AChE were subsequently investigated using a combination of time resolved fluorescence spectroscopy and X-ray crystallography. Our findings show that HI-6 binds to tabun inhibited Homo sapiens AChE (hAChE) with an IC50 value of 300muM and suggest that the reactive nucleophilic moiety of HI-6 is excluded from the phosphorus atom of tabun. We propose that a conformational mobility of the side-chains of Phe338 and His447 is a common feature in nerve-agent adducts of AChE. We also suggest that the conformational mobility allow HI-6 to reactivate conjugates of cyclosarin and Russian VX while a reduced mobility in tabun conjugated AChE results in steric hindrance that prevents efficient reactivation. Catalytic-site conformational equilibrium in nerve-agent adducts of acetylcholinesterase: Possible implications for the HI-6 antidote substrate specificity.,Artursson E, Andersson PO, Akfur C, Linusson A, Borjegren S, Ekstrom F Biochem Pharmacol. 2013 Jan 29. pii: S0006-2952(13)00053-1. doi:, 10.1016/j.bcp.2013.01.016. PMID:23376121 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Acetylcholinesterase 3D structures

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