Cross-Species Mutant Polypeptide Screening for Subtle Activity Shifts
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Solution Overview
Problem
Existing methods for protein evolution, such as site-directed mutagenesis and molecular evolution, struggle to accurately measure subtle performance changes in proteins, especially when sensitive assays are lacking, leading to inefficiencies in screening and cloning due to the rapid increase in combinations of mutations.
Innovation Solution
A method involving the generation and screening of mutant polypeptides across species, utilizing comprehensive mutagenesis and sequencing to identify cross-species active mutants, creating a functional map to optimize protein properties like binding affinity and immunogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single point mutations are generated and screened to improve protein characteristics, then beneficial amino acid substitutions can be identified, but the method requires accurate measurement of subtle performance changes which is not possible when sensitive assays do not exist
Solution Approach 1:
The patent uses an intermediary orthologous target from a different species as a mediator to amplify and make detectable the subtle performance changes of single point mutants. By testing mutant proteins against orthologous targets, the assay sensitivity is enhanced, enabling detection of subtle binding affinity changes that would be undetectable in the original system.
Solution Approach 2:
The patent replaces the direct mechanical/biochemical interaction assay (which lacks sensitivity) with a substituted assay system using orthologous proteins. This substitution allows indirect measurement of protein performance through cross-species binding interactions, which are more readily detectable.
2Productivity
If simultaneous mutations of several sites are performed to accelerate evolution, then the number of combinations increases quickly, but this reaches the limits of cloning efficiency and screening capability
Solution Approach 1:
The patent segments the protein evolution process into two distinct phases: first generating and screening single point mutants to identify beneficial substitutions, then recombining these validated mutations in subsequent rounds. This segmentation prevents the combinatorial explosion problem by limiting each screening round to manageable mutation numbers while still achieving multi-site optimization over time.
Solution Approach 2:
The patent performs preliminary screening of single point mutations before combining them into multi-mutant constructs. This preliminary action identifies which individual mutations are beneficial, allowing subsequent combinations to be rationally designed rather than randomly generated, thus reducing the effective search space and maintaining cloning/screening feasibility.
3Reliability
If comprehensive screening of mutant libraries is performed to identify upmutants, then improved protein characteristics can be achieved, but the process requires large numbers of clones to be screened which exceeds screening capability
Solution Approach 1:
The patent applies partial action by screening only single point mutants in the first round rather than all possible mutations. This partial screening approach identifies the most promising individual mutations, which are then combined in subsequent rounds. The excessive action comes in the form of generating sufficient single mutants to ensure coverage of all possible beneficial substitutions, even if this means creating more clones than can be screened in a single round.
Data Source
AI summary
The present invention is relevant to polypeptides and novel methods of polypeptide evolution. The present invention further relates to methods of identifying a cross-species mutant polypeptide from, or based upon, a template polypeptide.