Stabilized MHC I via Disulfide Bonding
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Solution Overview
Problem
Natural MHC I molecules are unstable, especially in the absence of a peptide or antigen binding, which complicates their use in analytical processes and stability in cell culture.
Innovation Solution
Modified MHC I molecules with covalent bonds between cysteine residues of the alpha chain and β2-microglobulin, forming disulfide bonds, which enhance stability and allow for expression without bound peptides, maintaining native conformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If natural MHC I molecules are used without covalent bonding, then the structure is simpler and more natural, but the stability is insufficient especially in the absence of cognate antigen
Solution Approach 1:
The patent applies composite materials by creating a hybrid MHC I molecule that combines the native alpha chain with a stabilized beta-2-microglobulin variant (S55V mutant). This composite structure integrates the antigen-binding functionality of the natural MHC I with the enhanced stability of the mutated beta-2-microglobulin, resolving the contradiction between maintaining natural simplicity and achieving improved stability.
Solution Approach 2:
The patent employs parameter changes by introducing a specific point mutation (S55V) in the beta-2-microglobulin sequence. This single amino acid substitution fundamentally alters the stability parameters of the MHC I molecule, enabling it to maintain structural integrity without requiring cognate antigen binding, thus resolving the stability-complexity contradiction through a minimal yet effective parameter modification.
2Stability of the object's composition
If MHC I molecules are stabilized through mutation, then stability increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent changes the manufacturing ease parameter by utilizing a single point mutation (S55V) in the beta-2-microglobulin sequence. This minimal genetic modification can be easily introduced through standard molecular biology techniques such as site-directed mutagenesis, allowing for straightforward cloning and expression in heterologous systems, thus maintaining ease of manufacture while achieving enhanced stability.
Solution Approach 2:
The stabilized beta-2-microglobulin (S55V) serves multiple functions: it provides structural stability to the MHC I molecule, enables proper folding and assembly with the alpha chain, and allows for expression in heterologous systems. This multi-functionality of a single mutated protein component simplifies the overall manufacturing process while achieving the desired stability.
3Adaptability or versatility
If MHC I molecules are produced without bound peptides, then analytical flexibility is improved, but the molecules are less stable in natural form
Solution Approach 1:
The patent resolves this contradiction by changing the stability parameter through the S55V mutation in beta-2-microglobulin. This parameter change enables the MHC I molecule to maintain stability in the peptide-free state, which is essential for analytical applications where peptides need to be added later. The mutation fundamentally alters the stability landscape, making the peptide-free form stable rather than unstable.
Solution Approach 2:
The patent applies preliminary action by pre-stabilizing the MHC I molecule structure through the S55V mutation before any peptide binding occurs. This preliminary stabilization ensures that the molecule is ready for subsequent peptide addition in analytical processes, maintaining both stability and analytical flexibility without requiring pre-bound peptides.
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 modified MHC I molecules exhibit increased stability and native conformation, enabling their use in analytical processes and expression in cell culture without bound peptides, improving their utility in diagnostic and research applications.
Implementation Method 1
The MHC I molecules comprise or consist of a heavy chain (alpha chain) and a β2-microglobulin, wherein the alpha chain may be devoid of a transmembrane domain to give a soluble MHC I molecule
Data Source
AI summary
Modified MHC I molecules that can be expressed in cell culture and can be more stable than natural MHC I molecules. An analytical process uses the modified MHC I molecules, e.g. for determination of antibodies in a serum sample directed against these MHC I molecules. MHC I is provided which has at least one covalent bond formed between a Cystein in the alpha chain and a Cystein in the β2-microglobulin.