O-Linked Sugar Chain Modification for Sialic Acid Linkage Analysis
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Solution Overview
Problem
Existing methods for examining the linking mode of sialic acid in O-linked sugar chains suffer from reduced accuracy due to incorrect modification of α2,6-sialic acid, leading to difficulties in distinguishing it from α2,3-sialic acid.
Innovation Solution
A method involving a two-step modification process is employed, where a dehydration-condensation agent lactonizes sialic acid, followed by an amidation reaction, specifically targeting α2,3-sialic acid and α2,6-sialic acid differently, and then releasing the modified O-linked sugar chains for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If modification is conducted on released O-linked sugar chains, then linking mode-specific modification can be achieved, but α2,6-sialic acid linked to N-acetylgalactosamine is incorrectly modified and accuracy of discrimination deteriorates
Solution Approach 1:
The patent applies preliminary action by conducting the linking mode-specific modification of sialic acid on the O-linked sugar chains while they are still attached to the glycoprotein, before releasing them. This preliminary modification step ensures that α2,6-sialic acid linked to N-acetylgalactosamine is correctly modified, avoiding the incorrect modification that occurs when modification is performed after release. The modified sugar chains are then released and analyzed, maintaining high discrimination accuracy.
2Ease of operation
If mass spectrometry is used to examine sugar chains, then analysis can be performed, but no change in mass occurs depending on linking mode so distinct examination is not possible
Solution Approach 1:
The patent applies parameter changes by introducing a chemical modification step that changes the mass parameter of sialic acid depending on its linking mode. Through linking mode-specific modification (lactonization for α2,3-sialic acid and amidation for α2,6-sialic acid), the sugar chains acquire different mass values that correspond to their respective linking modes. This enables mass spectrometry to distinctly examine and discriminate between different linking modes based on the induced mass differences.
3Ease of operation
If sialic acid is examined directly, then analysis can be conducted, but sialic acid has negative charge and is easily decomposed making examination difficult
Solution Approach 1:
The patent applies preliminary action by performing linking mode-specific modification on sialic acid while it is still attached to the glycoprotein structure, before any potential decomposition can occur. This preliminary modification stabilizes the sialic acid molecules and allows for reliable examination. The modified sugar chains are then released and analyzed by mass spectrometry, ensuring that the fragile sialic acid molecules are examined in a stable, modified state.
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
This approach allows for accurate discrimination and analysis of α2,6-sialic acid and α2,3-sialic acid in O-linked sugar chains, enhancing the accuracy of linking mode examination.
Implementation Method 1
a property that α2,3-sialic acid more easily generates intramolecular dehydration by a dehydration-condensation agent than α2,6-sialic acid is utilized, and thus α2,3-sialic acid is lactonized by intramolecular dehydration
Implementation Method 2
α2,6-sialic acid is reacted with a nucleophilic agent such as alcohol or amine
Data Source
AI summary
Provided is a method for analyzing an O-linked sugar chain subjected to linking mode-specific modification of sialic acid, the method including a modification step of adding a modifier that subjects the O-linked sugar chain to linking mode-specific modification of sialic acid, to a sample including a glycoprotein to which the O-linked sugar chain is linked, a releasing step of releasing the O-linked sugar chain subjected to linking mode-specific modification of sialic acid, from the glycoprotein, and an analysis step of analyzing the released O-linked sugar chain subjected to linking mode-specific modification of sialic acid.