Modified Haemoglobin Proteins for Oxygen Carrying Stability
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Solution Overview
Problem
Current haemoglobin-based oxygen therapeutics face issues such as rapid dissociation of tetramers to dimers, leading to kidney damage, and spontaneous oxidation of haem iron, resulting in oxidative stress and cytotoxicity, which limits their oxygen carrying capability and increases toxicity.
Innovation Solution
A modified oxygen-carrying protein with inserted or substituted redox-active amino acids, specifically tyrosine, histidine, phenylalanine, or tryptophan, to enhance the reduction of ferric (Fe3+) ions to ferrous (Fe2+) ions, improving stability and oxygen re-oxygenation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If native haemoglobin is used as an oxygen therapeutic, then oxygen carrying capability is provided, but the tetrameric form readily dissociates into dimeric form which is rapidly cleared by kidneys causing damage
Solution Approach 1:
The patent introduces inter-molecular disulphide bonds between cysteine residues on adjacent haemoglobin chains, creating covalently linked tetrameric structures. This segmentation approach strengthens the tetramer by forming specific covalent connections between subunits, preventing dissociation into dimers while maintaining oxygen carrying function.
Solution Approach 2:
The patent combines multiple stabilizing strategies including covalent disulphide bonding, non-covalent interactions through engineered amino acid pairs, and PEGylation to create a highly stable tetrameric structure. These merged approaches work synergistically to prevent dissociation while preserving oxygen transport capability.
2Quantity of substance
If haemoglobin-based oxygen carriers are used, then oxygen transport is achieved, but spontaneous oxidation of haem iron occurs converting ferrous form to ferric form resulting in oxidative stress and cytotoxicity
Solution Approach 1:
The patent introduces redox-active amino acid residues (tyrosine, histidine, phenylalanine, tryptophan) that can undergo reversible oxidation. These residues act as sacrificial antioxidants, undergoing oxidation themselves to protect the haem iron from harmful oxidation. The oxidative damage is converted from a harmful effect to a protective mechanism where the engineered residues absorb oxidative stress.
Solution Approach 2:
The redox-active amino acid residues serve as intermediary molecules between the haem iron and the oxidative environment. These intermediaries can donate electrons to reduce oxidized haem iron back to its functional ferrous state, mediating the redox balance and preventing accumulation of toxic oxidized forms.
3Reliability
If modifications are introduced to improve tetramer stability and reduce oxidation, then stability and reduced cytotoxicity are achieved, but protein structure complexity increases
Solution Approach 1:
The patent modifies specific amino acid parameters at defined positions in the haemoglobin sequence. Rather than global structural changes, targeted substitutions of cysteine, tyrosine, histidine, phenylalanine, or tryptophan residues at specific positions create stability and redox protection with minimal impact on overall protein structure and function.
Solution Approach 2:
The patent applies modifications locally at specific positions rather than throughout the entire protein. Disulphide bonds are formed at specific inter-subunit interfaces, and redox-active residues are introduced at localized positions near the haem group or at subunit interfaces, providing targeted stabilization without global structural 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
The modified protein exhibits enhanced stability and reduced cytotoxicity, maintaining improved oxygen carrying capability and rapid re-oxygenation, addressing the limitations of existing haemoglobin-based oxygen therapeutics.
Implementation Method 1
A modified oxygen-carrying protein with inserted or substituted redox-active amino acids, specifically tyrosine, histidine, phenylalanine, or tryptophan, to enhance the reduction of ferric (Fe3+) ions to ferrous (Fe2+) ions
Data Source
AI summary
The present invention relates to modified proteins e.g. oxygen-carrying proteins, with improved or enhanced, in comparison to a reference protein, reduction of a metal ion associated with the modified protein. The present invention also relates to methods of using such modified proteins and compositions comprising such proteins e.g. in therapy.