AAV Capsid Site-Specific Modification via Genetic Code Expansion

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Solution Overview

Problem

Current methods for modifying adeno-associated virus (AAV) capsid proteins to target specific cells face challenges such as low production yield, reduced vector titer, and altered interactions with host cells, necessitating a site-selective and non-destructive modification technique.

Innovation Solution

Incorporation of non-natural amino acids into specific sites of the AAV capsid protein VP1 using genetic code expansion techniques, allowing for site-specific modification while maintaining viral production and transduction ability, through the use of orthogonal amber mutant suppressor aminoacyl-tRNA synthase/tRNA pairs and click chemistry for labeling and targeting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If genetic modification of AAV capsid proteins is performed by insertion of targeting peptide motifs, then targeting capability to specific cell types is improved, but viral production yield and vector titer are reduced

Engineering Contradiction:
Improvetargeting capabilityVSAvoidviral production yield
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies local quality by introducing non-natural amino acids at specific localized positions on the capsid protein surface rather than general modifications. The genetic code expansion system allows site-specific incorporation of non-natural amino acids at predetermined locations (e.g., surface-exposed residues), enabling targeted functional modification without widespread structural disruption to the capsid assembly and viral production.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If genetic modification of AAV capsid proteins is performed by insertion of targeting peptide motifs, then targeting capability to specific cell types is improved, but vector titer is reduced

Engineering Contradiction:
Improvetargeting capabilityVSAvoidvector titer
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by introducing non-natural amino acids at specific localized positions on the capsid protein surface rather than general modifications. The genetic code expansion system allows site-specific incorporation of non-natural amino acids at predetermined locations (e.g., surface-exposed residues), enabling targeted functional modification without widespread structural disruption to the capsid assembly and viral production.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If genetic modification of AAV capsid proteins is performed by insertion of targeting peptide motifs, then targeting capability is improved, but interactions with host cells are altered

Engineering Contradiction:
Improvetargeting capabilityVSAvoidhost cell interaction stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by substituting specific amino acid residues with non-natural amino acids that have different chemical properties (e.g., aromatic, aliphatic, polar, charged groups). This allows precise modulation of capsid-host cell interactions at selected sites while maintaining overall capsid structure and function. The orthogonal tRNA/synthetase system ensures site-specific incorporation without affecting other amino acid positions, thereby preserving reliable host cell interactions elsewhere in the capsid.

Inventive Principle:
Principle #35Parameter changes

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

Enables site-specific modification of AAVs with non-natural amino acids, enhancing targeting capabilities and maintaining viral infectivity and production efficiency, allowing for improved gene therapy applications.

Implementation Method 1

a technology of expanding genetic code is developing in recent years, in which an amber termination codon (TAG) is used to encode a variety of non-natural amino acids and to perform site-specific incorporation into organisms in vivo

Methodology Applied
Scientific EffectGenetic code expansion:

Implementation Method 2

an non-natural amino acid is coupled to the fluorescence labeling molecule via a click chemistry

Methodology Applied
Scientific EffectClick chemistry:

Data Source

PatentEP3070095B1Adeno-associated virus with site-directed mutagenesis and site-directed modification, and preparation method and application therefor
Publication Date: 2021.04.28 PEKING UNIV
  • EP3070095B1 patent drawingFigure 1A~1B
  • EP3070095B1 patent drawingFigure 2A~2D
  • EP3070095B1 patent drawingFigure 3A~4

AI summary

The present invention relates to an adeno-associated virus with site-directed mutagenesis and site-specific modification, and a preparation method and uses thereof. Specifically, the present invention uses genetic code expansion techniques to incorporate non-natural amino acid into an adeno-associated virus capsid protein VP1 or fragment thereof, thereby obtaining an adeno-associated virus with site-directed mutagenesis using the non-natural amino acid. The adeno-associated virus with site-directed mutagenesis is equivalent to a wild-type virus in terms of production, transduction and mobility, can couple with other functional molecules, such as targeting molecules, and can carry a functional gene in a normal manner, which indicates that the adeno-associated virus with site-directed mutagenesis can be used as a tool adeno-associated virus, and applied in various aspects associated with adeno-associated virus such as finding adeno-associated virus binding proteins or using as target genetic therapy vector.