Modified Botulinum Neurotoxin Binding Specificity

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Solution Overview

Problem

Botulinum neurotoxins (BoNTs) used for treating neuromuscular disorders face limitations due to neutralizing antibody generation and adverse effects related to toxin diffusion, particularly at higher doses, necessitating enhanced specificity and efficacy to reduce off-target effects.

Innovation Solution

Modification of the receptor binding domain of Clostridial botulinum serotype B (BoNT/B) with specific substitution mutations, such as E1191M and S1199L, to enhance binding to human synaptotagmin II (Syt II) while reducing binding to human Syt I, thereby improving therapeutic efficacy and specificity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher doses of BoNT are used to treat muscle spasms, then therapeutic efficacy is improved, but neutralizing antibody generation increases and adverse effects occur

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoidneutralizing antibody generation and adverse effects

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the amino acid sequence of the BoNT/B receptor binding domain through specific substitutions (E1191M, S1199L, E1191Q) to alter its binding characteristics. These parameter changes in the molecular structure enable the toxin to achieve higher affinity for human Syt II receptors, thereby improving therapeutic efficacy at lower doses and reducing the harmful effects associated with higher dosing

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If toxin dose is reduced to minimize antibody generation and adverse effects, then safety is improved, but therapeutic efficacy decreases

Engineering Contradiction:

ImprovesafetyVSAvoidtherapeutic efficacy

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent modifies the receptor binding domain parameters through specific amino acid substitutions that enhance binding affinity for human Syt II. This parameter optimization allows the toxin to maintain high therapeutic efficacy at reduced doses, thereby resolving the contradiction between safety and productivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by making specific targeted modifications only to the receptor binding domain (HC region) while leaving the rest of the toxin structure unchanged. The specific amino acid positions (E1191, S1199) are modified to enhance human Syt II binding, creating a locally optimized toxin that achieves improved safety-efficacy balance without altering the entire molecule

Inventive Principle:

Principle #3Local quality

3Productivity

If BoNT/B is used to treat muscle spasms, then therapeutic effect is achieved, but binding to human Syt II is insufficient compared to rodent Syt II

Engineering Contradiction:

Improvetherapeutic effectVSAvoidbinding affinity to human Syt II

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by introducing specific amino acid substitutions (E1191M, S1199L, E1191Q) in the receptor binding domain that specifically enhance binding affinity for human Syt II. These parameter modifications address the species-specific binding difference, enabling BoNT/B to effectively bind human receptors while maintaining its protease activity and therapeutic effect

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses rodent Syt II binding characteristics as a template or model to guide the modification of BoNT/B. By analyzing the structural differences between rodent and human Syt II receptors, the patent copies the successful binding features from rodent interactions and applies them to human target receptors through rational amino acid substitutions

Inventive Principle:

Principle #26Copying

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 modified BoNT/B exhibits significantly enhanced binding to human Syt II, allowing for reduced toxin doses and decreased off-target effects, thereby improving therapeutic outcomes and safety.

Implementation Method 1

The modified BoNT/B exhibits significantly enhanced binding to human Syt II

Methodology Applied

Scientific EffectProtein-protein binding:

Data Source

PatentUS10844362B2Engineered botulinum neurotoxin

Publication Date: 2020.11.24 PRESIDENT & FELLOWS OF HARVARD COLLEGE

AI summary

Disclosed herein are botulinum neurotoxin (BoNT) polypeptides with a modified receptor binding domain of Clostridial botulinum serotype B (B-Hc), comprising one or more substitution mutations corresponding to substitution mutations in serotype B, strain 1, V1118M; Y1183M; E1191M; E1191I; E1191Q; E1191T; S1199Y; S1199F; S1199L; S1201V; or combinations thereof. Specific combination mutations include E1191M and S1199L, E1191M and S1199Y, E1191M and S1199F, E1191Q and S1199L, E1191Q and S1199Y, or E1191Q and S1199F. Other substitution mutations are also disclosed. Isolated modified receptor binding domains, chimeric molecules, pharmaceutical compositions, and methods of using the same are also disclosed.