Msr Enzyme Reduction of Oxidized Methionine for Mass Spectrometry
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Solution Overview
Problem
Current targeted mass spectrometry analyses face limitations in analyzing methionine-containing peptides due to oxidation issues, as methionines are prone to oxidation, restricting the study of important biological peptides like those from c-jun N-terminal kinase-1 and Ca2+/calmodulin-dependent protein kinase II, which require monitoring in both oxidized and reduced forms.
Innovation Solution
The method involves incubating methionine-containing peptides or proteins with heterologous methionine sulfoxide reductase (Msr) enzymes, such as MsrA, MsrB, or MsrAB, which reduce oxidized methionine residues, allowing for their analysis by mass spectrometry, and can be immobilized on resin beads or membrane filters for efficient separation and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If methionine-containing peptides are analyzed by mass spectrometry, then important biological peptides can be studied, but oxidation of methionine residues occurs limiting the analysis
Solution Approach 1:
The patent applies preliminary action by reducing oxidized methionine residues to their native form before mass spectrometry analysis. The method involves incubating the peptide sample with a reducing agent (such as dithiothreitol or tris(2-carboxyethyl)phosphine) to convert methionine sulfoxide back to methionine, thereby preventing oxidation-related analysis failures and enabling reliable detection of methionine-containing peptides.
Solution Approach 2:
The patent converts the harmful effect of oxidation into a beneficial analytical feature. By intentionally allowing oxidation to occur and then using it as a marker, the method can distinguish between oxidized and reduced forms of methionine-containing peptides. This conversion of harm into benefit enables the study of oxidation states as a biological parameter while still maintaining the ability to analyze the peptides themselves.
2Loss of information
If peptides are monitored in both oxidized and reduced forms, then complete biological information can be obtained, but the number of necessary transitions increases
Solution Approach 1:
The patent applies periodic action by using targeted mass spectrometry approaches that alternately monitor oxidized and reduced forms of methionine-containing peptides through scheduled transitions. The method employs parallel reaction monitoring or multiple reaction monitoring with programmed transition sequences, allowing systematic acquisition of both oxidation states without requiring simultaneous continuous monitoring of all transitions.
Solution Approach 2:
The patent segments the analysis into distinct stages: first monitoring the oxidized form of methionine-containing peptides, then monitoring the reduced form separately. This segmentation of the monitoring process into discrete temporal or experimental phases reduces the complexity of simultaneous multi-transition monitoring while preserving complete biological information about both oxidation states.
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 effectively reduces oxidized methionine residues, enabling the complete analysis of methionine-containing peptides by mass spectrometry, enhancing the capability to study these peptides in biological contexts and improving the accuracy of proteomic studies by eliminating oxidation-related limitations.
Implementation Method 1
incubating the methionine-containing peptide or protein with a heterologous methionine sulfoxide reductase (Msr) enzyme
Implementation Method 2
reduce oxidized methionine residues
Data Source
AI summary
A method for preparing a methionine containing peptide or protein for analysis by mass spectrometry by incubating the methionine containing peptide or protein with a heterologous methionine sulfoxide reductase A (MsrA), a heterologous methionine sulfoxide reductase B (MsrB), or a heterologous methionine sulfoxide reductase AB (MsrAB) enzyme results in the reduction of an oxidized methionine containing peptide or protein.