PMID: 30993792

Authors:

Bester SM, Adipietro KA, Funk VL, Myslinski J, Keul ND, Cheung J, Wilder PT, Wood ZA, Weber DJ, Height JJ, Pegan SD

Title:

The structural and biochemical impact of monomerizing human acetylcholinesterase.

Journal:

Protein Sci. 2019 Apr 16. doi: 10.1002/pro.3625.

Abstract:

Serving a critical role in neurotransmission, human acetylcholinesterase (hAChE) is the target of organophosphate (OP) nerve agents. Hence, there is an active interest in studying the mechanism of inhibition and recovery of enzymatic activity, which could lead to better countermeasures against nerve agents. Because hAChE is found in different oligomeric assemblies, certain approaches to studying it have been problematic. Herein, we examine the biochemical and structural impact that occurs when monomerizing hAChE by using two mutations: L380R/F535K. The activity of monomeric hAChE L380R/F535K and dimeric hAChE were determined to be comparable utilizing a modified Ellman Assay. To investigate the influence of subunit-subunit interactions on the structure of hAChE, a 2.1 a X-ray crystallographic structure was determined. Apart from minor shifts along the dimer interface, the overall structure of hAChE L380R/F535K mutant mirrors that of hAChE. To probe whether the plasticity of the active site was overtly impacted by monomerizing hAChE, the kinetics of inhibition with (PR/S )- VX and subsequent rescue of hAChE L380R/F535K activity with HI-6 were determined and found to be comparable to dimeric hAChE. Thus, hAChE L380R/F535K could be used as a substitute for the dimer when experimentally probing the ability of the hAChE active site to accommodate future nerve agent threats or judge the ability of new therapeutics to access the active site. This article is protected by copyright. All rights reserved.