PGA Chemical Tags for Precise Citrullination Site Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for analyzing protein citrullination, particularly in complex biological samples, lack precision and throughput, and existing mass spectrometry techniques face challenges in distinguishing citrullination from other modifications due to similar mass shifts, leading to misidentification of citrullination sites.
Innovation Solution
Development of phenylglyoxal-based alkyne (PGA) chemical tags that selectively react with ureido groups in citrullinated proteins, enabling high-confidence identification and quantification through mass spectrometry, combined with isotopic and isobaric tag labeling techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional antibody-based techniques (ELISA, IHC, WB) are used for citrullination analysis, then protein citrullination can be detected, but precise and high-throughput identification of low-abundance citrullinated proteins in complex biological samples is not achievable
Solution Approach 1:
The patent introduces phenylglyoxal-based chemical tags as intermediary molecules that selectively react with ureido groups in citrullinated proteins. These tags serve as mediators between the citrullinated proteins and detection methods, enabling specific enrichment and identification. The tags convert the difficult-to-detect citrullination modification into a detectable chemical handle that can be identified through mass spectrometry and other analytical techniques, thereby achieving both high precision and throughput.
2Productivity
If mass spectrometry-based bottom-up proteomics is used for large-scale analysis of PTMs, then analysis capability is improved, but accurate identification of citrullination sites is compromised due to similar mass shifts with deamidation and 13C isotopic peaks
Solution Approach 1:
The patent changes the detection parameter from direct mass shift measurement to chemical reactivity-based detection. By using phenylglyoxal-based tags that selectively react with ureido groups, the method transforms the mass spectrometry approach into a chemical derivatization approach. This parameter change allows differentiation between citrullination and deamidation based on chemical specificity rather than mass shift alone, resolving the interference issue while maintaining large-scale analysis capability.
3Difficulty of detecting and measuring
If conventional mass spectrometry is used to detect citrullination, then analysis can be performed, but the small mass shift of 0.984 Da makes it difficult to distinguish from deamidation and 13C isotopic peaks
Solution Approach 1:
The phenylglyoxal-based chemical tags act as intermediaries that amplify the detectability signal. Instead of detecting the small 0.984 Da mass shift directly, the tags create a larger, more distinct mass shift upon reaction with citrullinated proteins. This intermediary approach transforms the subtle mass difference into a more pronounced signal that can be easily distinguished from deamidation and isotopic peaks, thereby improving both detectability and discrimination accuracy.
Data Source
AI summary
The present invention provides phenylglyoxal-based alkyne (PGA) chemical tags exhibiting high specificity towards protein citrullination sites and other biomolecules containing similarly reactive functional groups. The PGA tags are able to bind to or derivatize biomolecules, such as polypeptides having one or more post-translational modifications (PTMs), such as citrullination. In particular, the PGA tags of the present invention have superior reactivity and selectivity towards ureido groups, and allow for the analysis of biomolecules containing ureido groups facilitated by click chemistry and mass spectrometry (MS) techniques and methods for qualitative and quantitative analysis of biological and clinical samples.