Isobaric Tandem Mass Tags for Proteomics Quantitation
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Solution Overview
Problem
Current isobaric tandem mass spectrometry tagging reagents for protein and peptide quantitation are costly, complex to synthesize, and limited in their ability to accurately quantify multiple samples due to spectral complexity and interference from adjacent isotopic peaks, particularly with 4-plex reagents.
Innovation Solution
Development of novel N, N-dimethylated amino acid based 8-plex and 16-plex isobaric tandem mass tagging reagents with a reporter group, balancing group, and amine reactive group, allowing for increased isotopic combinations and reduced synthesis steps, which reduces cost and enhances labeling efficiency and fragmentation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If isobaric labeling reagents (iTRAQ, TMT) are used for quantitative proteomics, then quantitation accuracy is improved, but synthesis complexity and cost increase
Solution Approach 1:
The labeling reagent is divided into three distinct functional modules: a reporter group containing isotopically labeled atoms for detection, a balancing group with complementary isotopic composition to maintain isobaric mass, and an amine reactive group for peptide attachment. This segmentation allows independent optimization of each function and simplifies the overall synthesis pathway.
Solution Approach 2:
The balancing group is designed to serve multiple functions: it maintains the isobaric mass relationship with the reporter group, provides structural stability to the reagent, and enables scalable synthesis through standardized building blocks. This multi-functionality reduces the number of specialized components needed.
2Adaptability or versatility
If 4-plex isobaric labeling reagents are used, then quantitation of multiple samples is enabled, but spectral complexity and interference from adjacent isotopic peaks increase
Solution Approach 1:
The reporter group incorporates specific isotopically labeled atoms (e.g., 13C, 15N, 2H) at defined positions to generate reporter ions with distinct mass-to-charge ratios. This localized isotopic labeling ensures that each of the four samples produces a uniquely identifiable signal while maintaining the same overall reagent mass, thereby enabling multiplexing without spectral overlap.
3Adaptability or versatility
If multiple heavy labeled reagents are used to compare more than two samples, then quantitation of multiple samples is improved, but mass spectral complexity increases
Solution Approach 1:
The invention changes the mass parameter distribution within the reagent structure: the reporter group contains lighter isotopically labeled atoms while the balancing group contains heavier isotopically labeled atoms in complementary amounts. This parameter change ensures that all four reagent variants remain isobaric (same total mass) while producing distinguishable reporter ions for multiplexed quantitation.
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 new reagents provide high quantitation efficacy with reduced costs, increased accuracy, and wider dynamic range, enabling simultaneous quantitation of multiple samples with improved protein identification and sequencing capabilities, and can be synthesized in fewer steps compared to existing commercial reagents.
Implementation Method 1
The tagging reagents are reacted with one or more samples containing a molecule of interest containing an amine group, such as a peptide
Implementation Method 2
MS is a technique growing in popularity in proteomics due, in part, to its ability to detect the presence of various chemical moieties
Implementation Method 3
Mass-difference labeling approaches introduce a mass difference for the same peptide by incorporating a light or heavy isotopic form of the labeling reagent
Data Source
AI summary
Compositions and methods of tagging peptides and other molecules using novel isobaric tandem mass tagging reagents, including novel N, N-dimethylated amino acid 8-plex and 16-plex isobaric tandem mass tagging reagents. The tagging reagents comprise: a) a reporter group having at least one atom that is optionally isotopically labeled; b) a balancing group, also having at least one atom that is optionally isotopically labeled, and c) an amine reactive group. The tagging reagents disclosed herein serve as attractive alternatives for isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tags (TMTs) due to their synthetic simplicity, labeling efficiency and improved fragmentation efficiency.