Isobaric Mass Labels for Multiplexed Peptide Identification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current isobaric mass tags for multiplexing in mass spectrometry analysis are limited to 10-plex and face challenges with small mass differences, leading to increased complexity in mass spectra and interference with peptide identification.
Innovation Solution
Development of sets of isotopomeric reactive tags with millidalton mass differences, allowing for higher multiplexing rates and reduced spectral complexity by using co-selectable isotopologue arrays, where each tag in a set has a unique integer mass and can be distinguished by mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If isobaric mass tags are used for multiplexing in mass spectrometry analysis, then the ability to analyze multiple samples simultaneously is improved, but the mass spectrum complexity increases and peptide identification becomes difficult
Solution Approach 1:
The mass tag is segmented into three distinct functional regions: a reporter ion region (provides unique mass signature for sample identification), a mass balance region (maintains isobaric mass equality across tags), and a peptide binding region (enables covalent attachment to peptide). This segmentation allows each region to fulfill its specific function independently, enabling high multiplexing while maintaining spectral simplicity.
Solution Approach 2:
The mass balance region acts as an intermediary component that compensates for the mass difference introduced by the reporter ion region. By adjusting the mass balance region to offset the reporter ion's mass variation, all mass tags maintain identical total mass (isobaric), preventing mass spectrum complexity while enabling multiplexing through unique reporter ions.
2Productivity
If isobaric mass tags with small mass differences are used, then higher multiplexing rates are achieved, but the mass differences become too small to resolve, leading to increased spectral complexity
Solution Approach 1:
Different regions of the mass tag have different mass characteristics optimized for their specific functions. The reporter ion region uses local quality variations (different masses) to encode sample identity, while the mass balance region uses complementary local quality (opposite mass difference) to compensate and maintain overall isobaric mass equality, enabling both high multiplexing and precise resolution.
Solution Approach 2:
The invention changes the mass parameter distribution within the tag structure. Instead of varying the total mass of the tag (which would affect the peptide's overall mass and create spectral complexity), the mass variation is localized to the reporter ion region, with compensating changes in the mass balance region that keep the total tag mass constant, thereby maintaining measurement precision while enabling high multiplexing.
3Productivity
If more mass tags are used to increase multiplexing, then more samples can be analyzed simultaneously, but the mass spectrum becomes more complex and interferes with peptide identification
Solution Approach 1:
The mass spectrometer is used in two distinct operational modes: first to detect the reporter ion (extracting sample identification information), then to detect the peptide fragment (obtaining peptide sequence information). This separation of detection functions allows multiplexing without compromising peptide identification, as the reporter ion detection occurs independently from the peptide fragment analysis.
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 novel forms of analysis for biological samples with significantly increased multiplexing rates beyond 10-plex, reducing spectral complexity and improving the identification of peptides by using tags with precise mass differences.
Implementation Method 1
each tag in a set has a unique integer mass and can be distinguished by mass spectrometry
Implementation Method 2
L is a bond cleavable by collision in a mass spectrometer
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a set of two or more mass labels, wherein each mass label comprises the formula: X-L-M-Re wherein X is a reporter moiety having an exact mass, L is a bond cleavable by collision in a mass spectrometer, M is a mass modifier, and Re is a) a reactive functionality for attaching the mass label to an analyte or b) the analyte, wherein each mass label in the set has an integer mass, wherein each mass label in the set has the same integer mass, and wherein the set comprises two or more subsets of mass labels, each subset comprising one, two or more mass labels, and wherein, when the subset comprises two or more mass labels, the exact mass of the reporter moiety X of each mass label in the subset is different from the exact mass of the reporter moiety X of the mass labels in the same subset and in all other subsets, and wherein each mass label is distinguishable by mass spectrometry.