Trioxane MS-Cleavable Cross-Linkers for Trimeric Interaction Mapping
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Solution Overview
Problem
Current cross-linking mass spectrometry methods face challenges in identifying and analyzing higher-order protein-protein interactions due to the heterogeneity and low abundance of cross-linked fragments, particularly with traditional non-cleavable cross-linkers, which complicate the identification process and introduce ambiguity in designating cross-linking sites.
Innovation Solution
Development of a novel trioxane-based MS-cleavable homotrifunctional cross-linker, such as TSTO, which can simultaneously target three proximal lysine residues, allowing for the capture and identification of trimeric protein interactions through unique and predictable fragmentation during collision-induced dissociation, simplifying the identification process using multistage mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional non-cleavable cross-linkers are used, then cross-linking stability is improved, but identification precision and analysis simplicity deteriorate due to heterogeneity and low abundance of cross-linked fragments
Solution Approach 1:
The cross-linker is designed with a central trioxane group connected to three reactive arms, each capable of independently cross-linking to lysine residues. This segmentation allows the cross-linker to form modular cross-linked products that can be systematically fragmented and identified through MSn analysis, resolving the identification precision issue while maintaining cross-linking stability.
Solution Approach 2:
The patent introduces MS-cleavable bonds with specific fragmentation properties that change the mass-to-charge ratio in predictable ways during collision-induced dissociation. This parameter change enables the differentiation of cross-linked fragments from background noise, significantly improving identification precision without compromising the stability of the cross-linked protein complexes.
2Productivity
If multifunctional cross-linkers targeting multiple residues are used, then productivity and information content are improved, but device complexity and analysis difficulty increase
Solution Approach 1:
The patent extracts and isolates specific fragment ions resulting from trioxane bond cleavage during MSn analysis. By focusing on these characteristic fragments with predictable mass shifts, the method simplifies the complex data from multifunctional cross-linking into identifiable patterns, reducing analysis difficulty while maintaining high information content.
Solution Approach 2:
The central trioxane group acts as an intermediary that connects three reactive arms while providing a unique fragmentation signature. This intermediary structure mediates between the complexity of multifunctional cross-linking and the simplicity of identification, as its predictable cleavage pattern serves as a fingerprint for detecting cross-linked products.
3Measurement precision
If higher-order cross-links are analyzed, then measurement precision and structural insights are improved, but heterogeneity and low abundance of fragments worsen the analysis
Solution Approach 1:
The patent employs multistage mass spectrometry (MSn) with sequential fragmentation steps. This periodic action allows for the stepwise breakdown of complex cross-linked products, progressively revealing structural information while enriching the signal of interest through successive isolation and fragmentation cycles, thereby overcoming low fragment abundance.
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 trioxane-based cross-linker enables the accurate identification of trimeric interactions, enhancing structural modeling with improved accuracy and precision, and has been successfully applied for in vivo cross-linking of HEK293 cells and mouse heart tissues.
Implementation Method 1
all types of TSTO cross-linked peptides display unique and predictable CID-induced fragmentation
Data Source
AI summary
The disclosure provides for mass spectrometry (MS)-cleavable trioxane-based cross-linkers, and uses thereof, including for protein-protein interaction studies using cross-linking mass spectrometry.