8AI7 image
Entry Detail
PDB ID:
8AI7
Keywords:
Title:
Structure of carbamoylated human butyrylcholinesterase upon reaction with 3-(((2-cycloheptylethyl)(methyl)amino)methyl)-1H-indol-7-yl N,N-dimethylcarbamate
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2022-07-25
Release Date:
2023-02-01
Method Details:
Experimental Method:
Resolution:
2.13 Å
R-Value Free:
0.21
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
I 4 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Cholinesterase
Mutations:N17Q, N455Q, N481Q, N486Q enginered mutations compared to mature wild type sequence to avoid too much N-glycozylation. Numeration on the maturated enzyme (devoid of the signal peptide)
Chain IDs:A (auth: F)
Chain Length:529
Number of Molecules:1
Biological Source:Homo sapiens
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
MKF A SER modified residue
Primary Citation
Pseudo-irreversible butyrylcholinesterase inhibitors: Structure-activity relationships, computational and crystallographic study of the N-dialkyl O-arylcarbamate warhead.
Eur.J.Med.Chem. 247 115048 115048 (2023)
PMID: 36586299 DOI: 10.1016/j.ejmech.2022.115048

Abstact

Alongside reversible butyrylcholinesterase inhibitors, a plethora of covalent butyrylcholinesterase inhibitors have been reported in the literature, typically pseudo-irreversible carbamates. For these latter, however, most cases lack full confirmation of their covalent mode of action. Additionally, the available reports regarding the structure-activity relationships of the O-arylcarbamate warhead are incomplete. Therefore, a follow-up on a series of pseudo-irreversible covalent carbamate human butyrylcholinesterase inhibitors and the structure-activity relationships of the N-dialkyl O-arylcarbamate warhead are presented in this study. The covalent mechanism of binding was tested by IC50 time-dependency profiles, and sequentially and increasingly confirmed by kinetic analysis, whole protein LC-MS, and crystallographic analysis. Computational studies provided valuable insights into steric constraints and identified problematic, bulky carbamate warheads that cannot reach and carbamoylate the catalytic Ser198. Quantum mechanical calculations provided further evidence that steric effects appear to be a key factor in determining the covalent binding behaviour of these carbamate cholinesterase inhibitors and their duration of action. Additionally, the introduction of a clickable terminal alkyne moiety into one of the carbamate N-substituents and in situ derivatisation with azide-containing fluorophore enabled fluorescent labelling of plasma human butyrylcholinesterase. This proof-of-concept study highlights the potential of this novel approach and for these compounds to be further developed as clickable molecular probes for investigating tissue localisation and activity of cholinesterases.

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