Optimized Degenerate Codon Sets for Library Complexity Reduction

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Solution Overview

Problem

Current methods for directed evolution of biological molecules face challenges in constructing and screening complete mutagenesis libraries due to the large sequence space, leading to reduced diversity and increased complexity, which complicates the identification of molecules with desired properties.

Innovation Solution

The use of optimized degenerate codon sets, such as NNT:VWG:TGG in a 16:6:1 ratio or VMA:NDT:WKG in a 6:12:4 ratio, to encode all possible amino acids efficiently, reducing library complexity and oversampling requirements during screening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complete mutagenesis of a reference polypeptide is performed to produce all possible single-amino acid sequence variants, then the diversity of the library is maximized, but the library complexity and the number of members to be screened increases dramatically

Engineering Contradiction:
Improvelibrary diversityVSAvoidlibrary complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the parameters of codon usage by employing optimized degenerate codon sets (such as NNT:VWG:TGG in 16:6:1 ratio or VMA:NDT:WKG in 6:12:4 ratio) that encode all 20 amino acids with reduced redundancy. This parameter change in codon composition reduces library complexity while maintaining complete amino acid diversity, resolving the contradiction between maximizing diversity and minimizing complexity.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the number of library members is reduced by applying logical filters and grouping amino acids, then the screening process is simplified, but the diversity of the library is reduced

Engineering Contradiction:
Improvescreening efficiencyVSAvoidlibrary diversity
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes to codon composition using optimized degenerate codon sets that encode all 20 amino acids with reduced redundancy. This allows maintaining full amino acid diversity while reducing the number of library members, thereby improving screening efficiency without sacrificing library diversity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If extensive oversampling is performed during screening to ensure adequate coverage, then the probability of identifying beneficial mutations increases, but the time and resources required for screening increase

Engineering Contradiction:
Improveidentification reliabilityVSAvoidscreening time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the codon composition parameters to use optimized degenerate codon sets that reduce library complexity. This reduction in complexity means fewer library members need to be screened to achieve adequate coverage, thereby reducing screening time and resources while maintaining the reliability of identifying beneficial mutations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3301208B1Reduced codon mutagenesis
Publication Date: 2020.11.04 CODEXIS INC
  • EP3301208B1 patent drawingFigure 1
  • EP3301208B1 patent drawingFigure 2
  • EP3301208B1 patent drawingFigure 3

AI summary

Methods and compositions that reduce complexity of libraries of variant biological molecules, that reduce oversampling of these libraries during screening and that improve screening efficiency are provided. Sets of efficient degenerate codon sets are provided that efficiently encode all, or nearly all canonical amino acids. Degenerate oligonucleotides comprising these codons are provided, as are polynucleotide variants. Variant pooling strategies are used during library construction. Logical filtering is applied to select codon sites for mutagenesis, or to select amino acid sets to be incorporated at such sites. Methods for reducing non-optimal oversampling during screening are provided.