4aqd
Crystal structure of fully glycosylated human butyrylcholinesterase
Structural highlights
DiseaseCHLE_HUMAN Defects in BCHE are the cause of butyrylcholinesterase deficiency (BChE deficiency) [MIM:177400. BChE deficiency is a metabolic disorder characterized by prolonged apnoea after the use of certain anesthetic drugs, including the muscle relaxants succinylcholine or mivacurium and other ester local anesthetics. The duration of the prolonged apnoea varies significantly depending on the extent of the enzyme deficiency. BChE deficiency is a multifactorial disorder. The hereditary condition is transmitted as an autosomal recessive trait. FunctionCHLE_HUMAN Esterase with broad substrate specificity. Contributes to the inactivation of the neurotransmitter acetylcholine. Can degrade neurotoxic organophosphate esters.[1] [2] Publication Abstract from PubMedButyrylcholinesterase (BChE) is a serine hydrolase that is present in all mammalian tissues. It can accommodate larger substrates or inhibitors than acetylcholinesterase (AChE), the enzyme responsible for hydrolysis of the neurotransmitter acetylcholine in the central nervous system and neuromuscular junctions. AChE is the specific target of organophosphorous pesticides and warfare nerve agents, and BChE is a stoichiometric bioscavenger. Conversion of BChE into a catalytic bioscavenger by rational design or designing reactivators specific to BChE required structural data obtained using a recombinant low-glycosylated human BChE expressed in Chinese hamster ovary cells. This expression system yields approximately 1 mg of pure enzyme per litre of cell culture. Here, we report an improved expression system using insect cells with a fourfold higher yield for truncated human BChE with all glycosylation sites present. We developed a fast purification protocol for the recombinant protein using huprine-based affinity chromatography, which is superior to the classical procainamide-based affinity. The purified BChE crystallized under different conditions and space group than the recombinant low-glycosylated protein produced in Chinese hamster ovary cells. The crystals diffracted to 2.5 A. The overall monomer structure is similar to the low-glycosylated structure except for the presence of the additional glycans. Remarkably, the carboxylic acid molecule systematically bound to the catalytic serine in the low-glycosylated structure is also present in this new structure, despite the different expression system, purification protocol and crystallization conditions. Database Structural data have been submitted to the Protein Data Bank under accession number pdb 4AQD. DNA sequence data for the synthetic gene have been submitted to GenBank under accession number JQ941878. Structured digital abstract * BChE and BChE bind by x-raycrystallography (View interaction). Human butyrylcholinesterase produced in insect cells: huprine-based affinity purification and crystal structure.,Brazzolotto X, Wandhammer M, Ronco C, Trovaslet M, Jean L, Lockridge O, Renard PY, Nachon F FEBS J. 2012 Aug;279(16):2905-16. doi: 10.1111/j.1742-4658.2012.08672.x. Epub, 2012 Jul 12. PMID:22726956[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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