Alpha-helix handle for protein nucleic acid bio-coupling
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Solution Overview
Problem
Current bio-coupling methods between proteins and nucleic acids face challenges due to low specificity and efficiency, particularly when using non-natural amino acids, as the nanoenvironment around proteins complicates the reactivity of these acids, making site-directed modification and optimization processes complex and inefficient.
Innovation Solution
A method involving an α-helix handle connected to a protein via a polypeptide, where a non-natural amino acid is inserted at a specific site through genetic code expansion, enabling efficient bio-coupling with nucleic acids using click chemistry, specifically a strain-promoted alkyne-azide cycloaddition reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-natural amino acids are used for bio-coupling between proteins and nucleic acids, then the modified group library is enriched and site-directed modification becomes possible, but the reactivity of these amino acids becomes unpredictable due to the complex nanoenvironment around the protein surface
Solution Approach 1:
The patent introduces an alpha-helix handle as an intermediary structure between the protein and the non-natural amino acid coupling group. This handle provides a controlled local environment that mediates the interaction, making the reactivity predictable while still allowing site-directed modification. The handle acts as a buffer that isolates the amino acid reactivity from the complex protein surface environment.
2Adaptability or versatility
If site-directed genetic mutations are used to introduce non-natural amino acids at any position of the protein, then any position can be modified, but the complex optimization and selection process of mutation sites is required and coupling efficiency remains low
Solution Approach 1:
The patent segments the protein modification system into distinct functional modules: the protein of interest, the alpha-helix handle with embedded non-natural amino acid, and the nucleic acid target. This segmentation allows the handle to be optimized independently for high coupling efficiency while the protein can be targeted at any position through genetic mutation, thus improving both versatility and productivity.
3Ease of manufacture
If natural amino acids are used for bio-coupling, then coupling is easy to achieve due to multiple modified group sites and high overall reactivity, but specificity in site selection is low and site-directed modification is almost impossible
Solution Approach 1:
The patent applies local quality by concentrating the reactivity and coupling capability specifically at the alpha-helix handle location, while other parts of the protein remain unchanged. The handle contains the non-natural amino acid with specific coupling groups, providing both the ease of coupling (like natural amino acids) and the site-specificity (unlike natural amino acids) simultaneously.
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 provides a controllable reaction environment, enhancing the bio-coupling efficiency between proteins and nucleic acids by avoiding the complexities of the protein surface environment, thereby achieving a more efficient and targeted connection.
Implementation Method 1
realizing an efficient bio-coupling between the protein and the nucleic acid by click chemistry
Data Source
AI summary
A method for improving a bio-coupling efficiency between a protein and a nucleic acid based on an α-helix handle includes the following steps. First, the handle carrying the non-natural amino acid (H-tag) is designed. Then, a recombinant expression plasmid encoding a fusion protein containing the H-tag and the protein to be tested is constructed. Subsequently, the fusion recombinant protein containing the non-natural amino acid in the H-tag is expressed and purified. Finally, the non-natural amino acid in the H-tag-fused protein and the coupling group on the nucleic acid substrate are efficiently connected by click chemistry. Thea-helix handle is used to provide a controllable reaction condition on the protein surface for the non-natural amino acid, avoiding the complex structure, charge and polar nanoenvironment around the surface of the protein to be tested.