Quadruplet Decoding tRNA Engineering via Anticodon Loop Optimization
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Solution Overview
Problem
Current methods for quadruplet decoding in genetic code expansion are inefficient and context-dependent, limiting the ability to translate four-base codons effectively, with existing suppressor tRNAs often causing frameshifts and having low efficiency in vivo.
Innovation Solution
Development of novel suppressor tRNA molecules encoded by specific sequences, including SEQ ID NOs: 1-21, 28-67, 88-97, and 131-145, and the use of phage-assisted continuing evolution (PACE) methods to engineer evolved quadruplet decoding tRNAs with improved efficiency and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If quadruplet decoding tRNAs are used to translate four-base codons, then the genetic code can be expanded, but translation efficiency is low and context-dependent
Solution Approach 1:
The patent modifies the anticodon loop structure of tRNA by changing its length and sequence composition to optimize quadruplet decoding. Specifically, tRNAs with 7-9 nucleotides in the anticodon loop were found to have improved translation efficiency compared to conventional tRNAs, demonstrating parameter changes in structural dimensions to resolve the efficiency contradiction
Solution Approach 2:
The patent employs phage-assisted continuous evolution (PACE) to dynamically optimize tRNA sequences over multiple generations. This evolutionary approach allows the tRNA population to adapt and improve translation efficiency continuously, transforming a static low-efficiency system into a dynamic optimizing system that resolves the efficiency limitation
2Adaptability or versatility
If suppressor tRNAs with one-bp insertion in anticodon loop are used, then quadruplet decoding capability is achieved, but frameshift occurs during translation
Solution Approach 1:
The patent applies local quality by making specific targeted modifications to the anticodon loop region while keeping the rest of the tRNA structure intact. The modifications are localized to the 7-9 nucleotide anticodon loop segment that directly interacts with the quadruplet codon, allowing quadruplet decoding capability while maintaining overall translation fidelity through preserved structural integrity
Solution Approach 2:
The patent uses PACE to create and select optimized copies of tRNA molecules over successive generations. Through this copying and selection process, frameshift-prone sequences are eliminated and replaced with high-fidelity copies that maintain quadruplet decoding capability without causing frameshift errors, thus improving translation reliability
3Adaptability or versatility
If existing suppressor tRNAs are used for quadruplet decoding, then some decoding capability is achieved, but efficiency in vivo is low
Solution Approach 1:
The patent implements self-service through autonomous evolutionary optimization within the PACE system. The tRNA population evolves its own optimized sequences for in vivo function without external intervention, with the system automatically selecting variants that demonstrate improved translation efficiency in the cellular environment, thereby resolving the low in vivo efficiency problem
Solution Approach 2:
The patent incorporates feedback mechanisms where translation efficiency is continuously monitored and used to guide further evolutionary optimization. The PACE system uses translational output as feedback to select and amplify superior tRNA variants, creating a closed-loop optimization process that progressively improves in vivo translation efficiency while maintaining quadruplet decoding capability
Data Source
AI summary
The invention, in part, includes compositions comprising quadruplet decoding tRNAs and their encoding sequences. The invention also includes assay methods to assess quadruplet decoding as well as methods of preparing quadruplet decoding suppression tRNAs.