Sequence-Defined Polymers: pAzF Restoration After Azide Reduction
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Solution Overview
Problem
The reduction of azide moieties in non-standard amino acids (nsAAs) such as para-azido-phenylalanine (pAzF) during protein expression leads to heterogeneous protein products, reducing yield and purity, especially when multiple azide moieties are encoded in a single protein.
Innovation Solution
The use of imidazole-1-sulfonyl azide (ISAz) under specific aqueous conditions to restore reduced or degraded pAzF residues in polypeptides, maintaining purity and enabling further functionalization through reactions like copper-catalyzed azide-alkyne cycloaddition and Staudinger ligation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If protein expression is performed using nonstandard amino acids containing azide groups, then new chemistries and functionalization applications are enabled, but heterogeneous protein products are formed due to azide reduction, reducing yield and purity
Solution Approach 1:
The patent applies preliminary action by expressing the protein in a recoded organism that lacks the machinery to reduce azide groups, preventing the harmful reduction before it occurs. The organism's translation system is engineered to incorporate pAzF without subsequent reduction, ensuring homogeneous product formation from the outset rather than attempting to correct heterogeneity after protein expression.
Solution Approach 2:
The patent changes the biological parameter of the expression system by using a genomically recoded organism (GRO) where the UAG codon reading machinery has been deleted or inactivated. This parameter change in the organism's genetic code prevents azide reduction, allowing high-purity pAzF-containing proteins to be produced while maintaining the versatility of azide chemistry for functionalization.
2Adaptability or versatility
If multiple instances of azide moieties are encoded in a single protein, then more extensive functionalization is possible, but heterogeneous products are formed due to reduction, magnifying the challenges
Solution Approach 1:
The patent prevents azide reduction at the outset by using a recoded organism that lacks reduction machinery, ensuring that all multiple azide moieties in the protein remain intact and homogeneous throughout the expression process, enabling reliable extensive functionalization.
Solution Approach 2:
The patent modifies the organism's genetic code parameter by deleting or inactivating the UAG codon reading machinery, which prevents azide reduction. This parameter change ensures that proteins with multiple azide moieties are produced with high homogeneity and reliability, enabling comprehensive functionalization at all designated sites.
3Ease of manufacture
If azide reduction occurs during protein expression, then the azide moiety is converted to amine, but this results in heterogeneous products and reduced yield of desired functionalized protein
Solution Approach 1:
The patent changes the biological parameter of the expression system by using a genomically recoded organism where the UAG codon reading machinery is deleted or inactivated. This prevents azide reduction during protein expression, ensuring high yield of the desired functionalized protein with intact azide groups for subsequent chemistry.
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
Enhances the purity and stability of pAzF-containing polypeptides, allowing for improved site-specific functionalization and extended half-life through lipid conjugation, thereby increasing the effectiveness of biotechnological applications.
Implementation Method 1
The use of imidazole-1-sulfonyl azide (ISAz) under specific aqueous conditions to restore reduced or degraded pAzF residues in polypeptides
Implementation Method 2
copper-catalyzed azide-alkyne cycloaddition
Implementation Method 3
extended half-life through lipid conjugation
Data Source
AI summary
Improvements and extensions of methods of making and using para-azido-phenylalanine (pAzF)-containing polypeptides, and compositions formed therefrom are provided. Disclosed improvements and extensions include increasing the purity of pAzF present in pAzF-containing polypeptides, extending the half-Life of pAzF-containing polypeptides, and methods of making phosphoramidate (pnY)-containing polypeptides.