Site-Selective Peptide Coupling via Furan-Hydrazine Activation
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Solution Overview
Problem
Current methods for site-selective coupling of peptides face challenges such as selectivity issues due to naturally occurring nucleophilic residues, instability of thiomaleimide bonds, and the need for catalysts or excess reagents in carbonyl modifications, as well as interference from copper in click reactions, limiting their applicability in biological assays.
Innovation Solution
A method involving the activation of a furan moiety with a singlet oxygen signal followed by reaction with a hydrazine or hydroxylamine moiety for site-selective coupling, allowing for specific and efficient conjugation under physiological conditions without side reactions, and enabling the formation of stable conjugates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If maleimide conjugation with thiols is used for selective conjugation, then site-selectivity is improved, but stability of the resulting bond deteriorates due to susceptibility to spontaneous hydrolysis
Solution Approach 1:
The patent changes the chemical parameters of the conjugation system by replacing maleimide-thiol chemistry with furan-hydrazine chemistry. The furan moiety is activated to a furanone intermediate that reacts with hydrazine to form a stable hydrazone bond, eliminating the hydrolysis susceptibility of maleimide bonds while maintaining site-selectivity through the unique reactivity of the furan-hydrazine pair
Solution Approach 2:
The activated furanone intermediate serves as a transient, highly reactive species that forms only temporarily during the conjugation process. This short-lived intermediate enables selective reaction with hydrazine at the desired site without forming stable side products, allowing precise control over conjugation location while ensuring bond stability in the final product
2Manufacturing precision
If carbonyl condensation reactions are used for conjugation, then site-selectivity can be achieved, but reaction efficiency deteriorates due to sluggish reactivity in aqueous solutions at neutral pH requiring catalysts or excess reagents
Solution Approach 1:
The patent changes the reaction parameters by using furan activation to furanone intermediates, which exhibit enhanced electrophilicity compared to standard carbonyl groups. This allows the reaction to proceed efficiently at neutral pH in aqueous solutions without requiring catalysts or excess reagents, while maintaining site-selectivity through the specific activation of the furan moiety
Solution Approach 2:
The furan moiety is pre-activated to a furanone intermediate before reacting with the hydrazine-containing second agent. This preliminary activation step creates a highly reactive electrophilic center that readily reacts with nucleophilic hydrazine under physiological conditions, eliminating the need for catalysts or excess reagents while ensuring complete reaction
3Productivity
If click 1,3-dipolar cycloaddition between alkynes and azides is used, then reaction efficiency is improved, but purity deteriorates due to copper interference in biological assays
Solution Approach 1:
The patent extracts and removes copper from the conjugation system by replacing the copper-catalyzed click chemistry with a copper-free furan-hydrazine conjugation method. The furan activation and subsequent reaction with hydrazine proceeds without copper catalyst, eliminating copper contamination while maintaining high reaction efficiency and enabling direct application in biological assays
Solution Approach 2:
The activated furanone intermediate serves as a copper-free mediator that enables efficient conjugation between the furan-containing first agent and hydrazine-containing second agent. This intermediary species facilitates rapid reaction under physiological conditions without requiring copper catalyst, thereby eliminating harmful copper interference in biological systems
4Ease of operation
If naturally available nucleophilic biomolecule functionalities are used for conjugation, then ease of operation is improved, but selectivity deteriorates due to selectivity problems from multiple nucleophilic residues
Solution Approach 1:
The patent applies local quality by introducing a furan moiety at a specific location within the first agent (peptide or protein). This localized functional group provides a unique chemical signature that can be selectively activated and conjugated at that specific site, while leaving all other naturally occurring nucleophilic residues unchanged and non-reactive under the conjugation conditions
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
This method enables high specificity and efficiency in peptide labeling, preserving bioactivity and allowing conjugation in physiological conditions, resulting in stable and high-yield conjugates suitable for intracellular applications.
Implementation Method 1
contacting a first agent comprising at least one furan moiety with an activation signal, thereby activating said furan moiety to an activated furan moiety
Data Source
AI summary
The present invention relates to a method for site-selective coupling of a first agent to a second agent, comprising the steps of: contacting a first agent comprising at least one furan moiety with an activation signal and with a second agent comprising at least one hydrazine moiety or at least one hydroxylamine moiety, thereby activating said furan moiety to an activated furan moiety; and reacting said activated furan moiety with the hydrazine moiety or the hydroxylamine moiety, thereby site-selectively coupling said first agent to said second agent.