Crystal Structure of Snake Venom Acetylcholinesterase in Complex with Inhibitory Antibody Fragment Fab410 Bound at the Peripheral Site EVIDENCE FOR OPEN AND CLOSED STATES OF A BACK DOOR CHANNEL - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 2015

Crystal Structure of Snake Venom Acetylcholinesterase in Complex with Inhibitory Antibody Fragment Fab410 Bound at the Peripheral Site EVIDENCE FOR OPEN AND CLOSED STATES OF A BACK DOOR CHANNEL

Résumé

The acetylcholinesterase found in the venom of Bungarus fas- ciatus (BfAChE) is produced as a soluble, non-amphiphilic monomer with a canonical catalytic domain but a distinct C terminus compared with the other vertebrate enzymes. More- over, the peripheral anionic site of BfAChE, a surface site located at the active site gorge entrance, bears two substitutions altering sensitivity to cationic inhibitors. Antibody Elec410, generated against Electrophorus electricus acetylcholinesterase (EeAChE), inhibits EeAChE and BfAChE by binding to their peripheral sites. However, both complexes retain significant residual catalytic activity, suggesting incomplete gorge occlu- sion by bound antibody and/or high frequency back door open- ing. To explore a novel acetylcholinesterase species, ascertain the molecular bases of inhibition by Elec410, and document the determinants and mechanisms for back door opening, we solved a 2.7-Å resolution crystal structure of natural BfAChE in com- plex with antibody fragment Fab410. Crystalline BfAChE forms the canonical dimer found in all acetylcholinesterase structures. Equally represented open and closed states of a back door chan- nel, associated with alternate positions of a tyrosine phenol ring at the active site base, coexist in each subunit. At the BfAChE molecular surface, Fab410 is seated on the long -loop between two N-glycan chains and partially occludes the gorge entrance, a position that fully reflects the available mutagenesis and bio- chemical data. Experimentally based flexible molecular docking supports a similar Fab410 binding mode onto the EeAChE anti- gen. These data document the molecular and dynamic peculiar- ities of BfAChE with high frequency back door opening, and the mode of action of Elec410 as one of the largest peptidic inhibi- tors targeting the acetylcholinesterase peripheral site.
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hal-01439005 , version 1 (11-07-2024)

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Yves Bourne, Ludovic Renault, Pascale Marchot. Crystal Structure of Snake Venom Acetylcholinesterase in Complex with Inhibitory Antibody Fragment Fab410 Bound at the Peripheral Site EVIDENCE FOR OPEN AND CLOSED STATES OF A BACK DOOR CHANNEL. Journal of Biological Chemistry, 2015, 290 (3), pp.1522-1535. ⟨10.1074/jbc.M114.603902⟩. ⟨hal-01439005⟩
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