Multi-Stage Glycan MS for Protonated Isomer Assignment
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Solution Overview
Problem
Current mass spectrometry techniques face challenges in distinguishing among the numerous potential isomeric structures of glycans due to their inability to provide full information on branching patterns, linkage information, or stereochemistry, especially for intact glycoconjugates analyzed as protonated ions, leading to misinterpretation of data from gas-phase rearrangement reactions.
Innovation Solution
The use of advanced techniques such as ion mobility-mass spectrometry (IM-MS), gas-phase hydrogen/deuterium exchange (gHDX), and ultraviolet photodissociation, combined with tandem mass spectrometry and liquid chromatography, to analyze glycan structures, allowing for the resolution of structural isomers and site-specific localization of glycan structural isomers within glycoproteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mass spectrometry is used to analyze glycans, then mass measurement is obtained, but the ability to distinguish among isomeric structures is lost
Solution Approach 1:
The patent applies segmentation by performing multiple rounds of tandem mass spectrometry (MS2, MS3, MS4) to progressively fragment the glycan structure into smaller pieces. Each fragmentation round provides specific structural information about different regions of the glycan, enabling comprehensive characterization of branching patterns, linkages, and stereochemistry that cannot be obtained from a single mass measurement.
Solution Approach 2:
The patent introduces ion mobility spectrometry as an additional dimension of separation based on the drift time of ions through a buffer gas. This adds a new parameter (drift time) to distinguish isomers that have identical mass but different three-dimensional conformations, thereby resolving isomeric structures that traditional MS cannot differentiate.
2Reliability
If protonated glycan ions are analyzed by tandem MS, then structural information is obtained, but gas-phase rearrangement reactions cause misinterpretation
Solution Approach 1:
The patent changes the charge state parameter by analyzing sodiated glycan ions instead of protonated ions. This parameter change fundamentally alters the gas-phase chemistry, preventing rearrangement reactions and fucose migration that occur with protonated ions, thereby providing more reliable structural information.
Solution Approach 2:
The patent uses sodiation (addition of Na+ ions) as an intermediary approach to modify the glycan ions. The sodium adducts serve as a mediator that prevents harmful rearrangement reactions while still allowing structural information to be obtained through characteristic fragmentation patterns, thus improving reliability.
3Loss of information
If intact glycoconjugates are analyzed, then complete glycan-protein information is obtained, but full structural characterization including branching and stereochemistry is impossible
Solution Approach 1:
The patent segments the intact glycoconjugate into glycan fragments through multiple rounds of tandem mass spectrometry. By systematically breaking down the complex structure into smaller, analyzable pieces across MS2, MS3, and MS4 stages, the method recovers complete structural information about branching patterns, linkages, and stereochemistry while managing the complexity through stepwise analysis.
Solution Approach 2:
The patent adds ion mobility separation as another dimension to the analysis of intact glycoconjugates. This additional dimension provides conformational information that helps characterize the three-dimensional structure of the intact glycoconjugate, enabling full structural characterization without overwhelming system complexity.
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
These methods enable detailed characterization of glycan structures, resolving subtle isomeric variants and providing accurate structural information, thereby overcoming the limitations of traditional MS-based glycan analysis and preventing misinterpretation of data.
Implementation Method 1
Ion mobility with mass spectrometry (IM-MS) separates ions by their charge, size, and shape due to interactions with an inert gas
Implementation Method 2
ultraviolet photodissociation
Implementation Method 3
Gas-phase hydrogen/deuterium exchange (gHDX), which tracks the exchangeability of various labile protons in an ion
Implementation Method 4
tandem MS is incapable of providing full information on the branching pattern, linkage information, or stereochemistry of the glycan
Data Source
AI summary
The present disclosure provides a method of analyzing the structure of a glycan sample, the method including: receiving data indicative of one or more spectra of mass-to-charge ratio (m/z) versus relative abundance of the glycan sample from a mass spectrometer (MS) instrument; generating a ratio according to the following Equation:aa+bwherein a is a magnitude of one or more first peaks in the one or more spectra and b is the magnitude of one or more second peaks in the one or more spectra; determining that the ratio is within a range of a predetermined ratio; based on determining that the ratio is within the range of the predetermined ratio, determining that a predetermined structural characteristic is present in the glycan sample; and outputting an indication of the predetermined structural characteristic in the glycan sample.