Reversible Streptavidin Enrichment for Crosslinked Peptides
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Solution Overview
Problem
Current crosslinking mass spectrometry methods face challenges in efficiently enriching low-abundance crosslinked peptide pairs due to the non-reversible nature of the streptavidin-biotin system, which often requires extreme denaturing conditions, damaging sensitive biological samples and complicating analysis, especially in complex biological samples like whole cells or organelles.
Innovation Solution
A reversible streptavidin-based analyte enrichment system using a trifunctional crosslinking agent with desthiobiotin as an affinity group, allowing for competitive elution under mild conditions, thereby enabling efficient enrichment and analysis of crosslinked peptides without chemical cleavage, which maintains the integrity of the peptides for mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extreme denaturing conditions are used to reverse the streptavidin-biotin interaction, then the interaction can be reversed, but the biological sample is destroyed and background contamination increases
Solution Approach 1:
The patent changes the chemical parameter of the biotin molecule by using desthiobiotin instead of conventional biotin. This structural modification reduces the binding affinity to streptavidin, allowing reversal under mild physiological conditions rather than extreme denaturing conditions, thus preserving the biological sample integrity
Solution Approach 2:
The patent employs a disposable crosslinking reagent containing desthiobiotin that can be easily removed after enrichment. The reagent serves its purpose during the enrichment process and can be discarded or washed away without requiring harsh reversal conditions, simplifying the overall process and protecting the sample
2Reliability
If conventional biotin is used for enrichment, then high affinity and specificity are achieved, but hydrophobicity and insolubility problems arise
Solution Approach 1:
The patent modifies the chemical structure of biotin by replacing the sulfur atom in the thietane ring with a carbon atom to create desthiobiotin. This structural change reduces hydrophobicity and improves water solubility while maintaining sufficient binding affinity for streptavidin, eliminating the harmful effects of conventional biotin
3Reliability
If biotin is used in crosslinking reagents, then enrichment capability is achieved, but oxidation occurs under mass spectrometry conditions
Solution Approach 1:
The patent changes the chemical composition of biotin by removing the susceptible thietane sulfur ring, creating desthiobiotin with enhanced chemical stability. This modification eliminates the oxidation problem that occurs with conventional biotin under mass spectrometry conditions, particularly electrospray ionization, while preserving the enrichment functionality
Solution Approach 2:
The desthiobiotin-containing crosslinking reagent is designed as a single-use component that can be easily removed after enrichment. This disposable approach avoids the need for complex removal procedures and prevents oxidation-related complications during subsequent mass spectrometry analysis
4Measurement precision
If crosslinked peptide pairs are enriched from complex mixtures, then detection sensitivity is improved, but the complexity of the enrichment procedure increases
Solution Approach 1:
The patent combines multiple functions into a single crosslinking reagent molecule: the crosslinking functionality (reactive groups), the enrichment tag (desthiobiotin), and the spacer arm. This unified design allows simultaneous crosslinking and enrichment in one step, eliminating the need for separate tagging procedures and reducing overall procedural complexity
Solution Approach 2:
The desthiobiotin-containing crosslinking reagent serves multiple purposes: it crosslinks proximal amino acid residues, provides streptavidin-binding capability for enrichment, and maintains chemical stability for mass spectrometry analysis. This multi-functional design simplifies the overall workflow while improving detection sensitivity
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 approach allows for high-efficiency enrichment and analysis of crosslinked peptides in complex biological samples, maintaining peptide integrity and reducing sample damage, thereby improving the detection of crosslinked peptides in mass spectrometry.
Implementation Method 1
The streptavidin-biotin interaction is the strongest non-covalent biological interaction known (Kd ~ 10-14 M)
Implementation Method 2
Methods attempting to reverse the interaction include extreme denaturing conditions... However, the strength of the interaction becomes a liability when reversal of the interaction is desired
Data Source
AI summary
It is provided a reversible streptavidin based analyte enrichment system for use in crosslinking mass spectrometry analysis, in particular for enriching at least parts of crosslinked peptides pairs in mass spectrometry analysis, and a method of enriching at least parts of crosslinked peptides pairs, in particular for use in crosslinking mass spectroscopy analysis.