Reversible Crosslinking Reagents for Protein Interaction Mapping
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Solution Overview
Problem
Current methods for studying protein-protein interactions, such as photocrosslinking, face challenges including inefficient crosslinking reagents, difficulty in capturing and purifying crosslinked products, and limitations in detecting protein-protein interactions without protein purification, especially in complex cellular environments.
Innovation Solution
Development of novel reversible crosslinking reagents with modular spacer groups and specific photocrosslinking moieties, such as trifluoromethyl phenyldiazirine or perfluorinated phenylazide, allowing for efficient labeling and detection of protein-protein interactions, along with methods for in vivo crosslinking and multi-dimensional detection of crosslinked peptides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photocrosslinking reagents are used, then crosslinking can be achieved, but crosslinking efficiency is low and the reagents are not widely used due to difficult synthetic procedures and radioactivity
Solution Approach 1:
The patent modifies the chemical structure of photocrosslinking reagents by replacing radioactive labels with non-radioactive alternatives (e.g., fluorophores, biotin), and by optimizing the photoreactive groups and spacer lengths to enhance crosslinking efficiency while simplifying synthesis procedures
Solution Approach 2:
The invention creates composite crosslinking reagents that combine multiple functional moieties (photoreactive groups, spacers, detection tags) into single molecules, enabling simultaneous crosslinking and detection capabilities while improving overall efficiency
2Measurement precision
If crosslinking reagents are used to study transient protein-protein interactions, then interaction sites can be identified, but difficulty in capturing and purifying crosslinked products limits detection sensitivity
Solution Approach 1:
The patent introduces affinity tags (such as biotin) as intermediaries that facilitate the capture and purification of crosslinked protein products through high-affinity binding to streptavidin, enabling sensitive detection of transient interactions
Solution Approach 2:
The invention incorporates fluorophores and other chromogenic tags into crosslinking reagents, allowing direct visualization and detection of crosslinked products through color or fluorescence changes, enhancing measurement sensitivity
3Measurement precision
If protein purification is performed before crosslinking, then detection sensitivity improves, but the ability to study interactions in complex cellular environments is lost
Solution Approach 1:
The patent designs crosslinking reagents with built-in purification handles (affinity tags) that enable self-purification of crosslinked products directly from complex cellular lysates, eliminating the need for pre-purification while maintaining detection sensitivity
Solution Approach 2:
The invention creates universal crosslinking reagents that can function effectively in both purified and crude cellular environments, adapting to different experimental conditions without requiring system-specific optimization
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
Enables accurate and sensitive mapping of protein-protein interaction sites at the molecular level, even in non-purified protein systems, enhancing the understanding of protein functionalities and interactions under various conditions.
Implementation Method 1
DTDA is able to form a disulfide bond with accessible cysteines. In combination with site-specific rhodopsin mutants, DTDA can be targeted to unique positions in the protein. In addition, following the formation of carbene, the radioactive label can be transferred to the site of insertion after cleavage of the disulfide bond.
Implementation Method 2
Covalent crosslinking using photoactivable reagents is a preferred method for studying transient protein-protein interactions due to their highly reactive and non-specific insertion properties with any proximal C—H bond.
Implementation Method 3
DTDA is able to form a disulfide bond with accessible cysteines.
Data Source
AI summary
The invention provides reagents, methods, and compositions for studying protein-protein interactions. The inventive system and methods allow the analysis of protein-protein interactions in vivo and in vitro. Advantages offered by various embodiments of the inventive system and methods compared to existing photocrosslinking approaches include, for example, (i) novel reversible crosslinking reagents that allow easy isolation, purification, and enrichment of the crosslinked products; (ii) trifiuoromethyl phenyldiazirine- or perfluorinaled phenylazide-based photocrosslinking reagents that provide high specific labeling, no side product, and higher photocrosslinking efficiency; (iii) versatile spacer groups that allow systematic contact site mapping; (iv) novel methods for isolating, purifying, and detecting crosslinked products based on the reversible-link chemistry; and (v) the ability to study the interaction sites in vitro, in situ, or in vivo.