BChE Mutants Enhancing Cocaine Hydrolysis Efficiency
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Solution Overview
Problem
Current pharmacological treatments for cocaine abuse are ineffective due to challenges in blocking cocaine's receptor/transporter blockade, and existing butyrylcholinesterase (BChE) variants have limited catalytic activity against the (-)-cocaine enantiomer, leading to prolonged cocaine exposure and toxicity.
Innovation Solution
Development of BChE polypeptide variants with specific amino acid substitutions, such as A199S, F227S, S287G, A328W, and Y332G, which significantly enhance catalytic efficiency for (-)-cocaine hydrolysis, offering a higher fold increase compared to wild-type BChE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wild-type BChE is used for cocaine metabolism, then the enzyme can hydrolyze cocaine at the benzoyl ester group, but the catalytic activity against (-)-cocaine is three orders-of-magnitude lower compared to (+)-cocaine, resulting in prolonged cocaine half-life and toxicity
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of BChE through site-directed mutagenesis. Specific residues (199, 227, 285, 286, 287, 328, 332, 441) are mutated to alter the enzyme's catalytic properties. The mutations change the chemical environment of the catalytic gorge, improving binding affinity and catalytic efficiency for (-)-cocaine by over 100-fold compared to wild-type BChE, thereby reducing cocaine half-life
Solution Approach 2:
The patent applies local quality by making specific localized changes to the BChE structure. Rather than changing the entire enzyme, only 7-8 specific amino acid residues in the catalytic gorge region are mutated. These localized mutations (e.g., A199S, F227S, S287G, A328W, Y332G) create a more complementary fit for (-)-cocaine while maintaining overall enzyme structure and function
2Productivity
If existing BChE mutants are used to increase catalytic activity, then some improvement over wild-type is achieved, but the catalytic efficiency is still insufficient to rapidly clear (-)-cocaine from plasma under overdose conditions
Solution Approach 1:
The patent applies merging by combining multiple beneficial mutations into a single BChE variant. Individual mutations that each provide modest improvement are consolidated into one enzyme with cumulative effects. The multi-mutant BChE combines mutations at positions 199, 227, 285, 286, 287, 328, 332, and 441, achieving synergistic improvement in catalytic efficiency that exceeds the sum of individual mutation effects
Solution Approach 2:
The patent applies composite materials by creating a chimeric enzyme structure. The BChE mutant incorporates amino acid sequences from different sources and modifications, forming a composite protein structure with optimized properties. The enzyme combines wild-type BChE framework with specific mutated regions, creating a hybrid structure that achieves superior catalytic performance for (-)-cocaine hydrolysis
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The enhanced BChE variants demonstrate a one-hundred-fold or more increase in cocaine hydrolysis catalytic efficiency, effectively lowering blood cocaine concentrations and addressing the limitations of existing treatments.
Implementation Method 1
The dominant pathway for cocaine metabolism in primates is butyrylcholinesterase (BChE)-catalyzed hydrolysis at the benzoyl ester group
Data Source
AI summary
Butyrylcholinesterase (BChE) polypeptide variants of the presently-disclosed subject matter have enhanced catalytic efficiency for (−)-cocaine, as compared to wild-type BChE. Pharmaceutical compositions of the presently-disclosed subject matter include a BChE polypeptide variant having an enhanced catalytic efficiency for (−)-cocaine. A method of the presently-disclosed subject matter for treating a cocaine-induced condition includes administering to an individual an effective amount of a BChE polypeptide variant, as disclosed herein, to lower blood cocaine concentration.