Source 1primary paper2021Nature Communications
Toolkit/genetic code expansion
genetic code expansion
Taxonomy: Technique Branch / Method. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
Genetic code expansion is an engineering method that enables incorporation of non-physiological amino acids into proteins. In the supplied evidence, it was used to design efficient incorporation systems in Bacillus subtilis and to generate a Cas9 variant that became full-length and active in cultured somatic cells only after BOC exposure.
Usefulness & Problems
Why this is useful
This method is useful for introducing chemical functionality not available in the canonical genetic code and for making protein activity dependent on exposure to a non-physiological amino acid. The cited studies indicate utility both for gaining biological insights in Bacillus subtilis and for conditional control of genome editing through BOC-dependent Cas9 activation.
Problem solved
Genetic code expansion addresses the problem of how to site-specifically encode non-physiological amino acids into proteins in living cells. The provided evidence also shows that it can solve the problem of restricting Cas9 activity until a defined chemical input, BOC, is present.
Published Workflows
Objective: Generate live-cell fluorescence biosensors for M2R and use them to resolve ligand-dependent conformational states and activation trajectories linked to G-protein activation and selectivity.
Why it works: The workflow is presented as working because genetically encoded and bioorthogonally labelled fluorescence biosensors allow real-time monitoring of agonist-promoted conformational changes across the receptor extracellular surface in intact cells.
agonist-dependent conformational equilibriamultiple active states of G-protein-bound M2Rligand-specific activation trajectoriesgenetic code expansionbioorthogonal labellingfluorescence-based biosensor generation
Stages
- 1.Generate fluorescence-based M2R biosensor panel(library_build)
To create receptor biosensors capable of reporting conformational changes in intact cells.
Selection: Construction of a panel of fluorescence-based biosensors using genetic code expansion and bioorthogonal labelling.
- 2.Real-time live-cell conformational monitoring(functional_characterization)
To observe receptor conformational changes in living cells rather than relying only on purified in vitro systems.
Selection: Monitor agonist-promoted conformational changes across the receptor extracellular surface in intact cells.
- 3.Resolve ligand-specific active-state equilibria and trajectories(secondary_characterization)
To connect observed conformational behavior to efficacy encoding and G-protein selectivity.
Selection: Determine how different agonists produce distinct active-state equilibria and activation trajectories of G-protein-bound M2R.
Taxonomy & Function
Primary hierarchy
Technique Branch
Method: A concrete method used to build, optimize, or evolve an engineered system.
Techniques
Computational DesignTarget processes
No target processes tagged yet.
Implementation Constraints
The evidence indicates implementation in Bacillus subtilis and in cultured somatic cells, with BOC exposure required for production of full-length active Cas9BOC. However, the supplied material does not specify the orthogonal tRNA/synthetase pair, codon reassignment strategy, construct architecture, or delivery method.
The supplied evidence does not provide quantitative incorporation efficiency, fidelity, dynamic range, or off-target effects. It also does not specify the exact non-physiological amino acid identity beyond BOC, the molecular components of the encoding system, or validation breadth across proteins and organisms.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Source 2primary paper2018Scientific Reports
Ranked Claims
The paper concerns designing efficient genetic code expansion in Bacillus subtilis to gain biological insights.
Designing efficient genetic code expansion in Bacillus subtilis to gain biological insights
Section: title
Genetic code expansion enabled BOC incorporation so that Cas9BOC was expressed in a full-length active form in cultured somatic cells only after BOC exposure.
Genetic code expansion permitted non-physiological BOC incorporation such that Cas9 (Cas9BOC) was expressed in a full-length, active form in cultured somatic cells only after BOC exposure.
Approval Evidence
2 sources2 linked approval claimsfirst-pass slug genetic-code-expansion
Designing efficient genetic code expansion in Bacillus subtilis to gain biological insights
Source:
Genetic code expansion permitted non-physiological BOC incorporation
Source:
study focussupports
The paper concerns designing efficient genetic code expansion in Bacillus subtilis to gain biological insights.
Designing efficient genetic code expansion in Bacillus subtilis to gain biological insights
Source:
conditional activitysupports
Genetic code expansion enabled BOC incorporation so that Cas9BOC was expressed in a full-length active form in cultured somatic cells only after BOC exposure.
Genetic code expansion permitted non-physiological BOC incorporation such that Cas9 (Cas9BOC) was expressed in a full-length, active form in cultured somatic cells only after BOC exposure.
Source:
Comparisons
Source-backed strengths
The evidence supports efficient genetic code expansion in Bacillus subtilis, indicating applicability beyond standard model expression contexts. It also supports a functional output in cultured somatic cells, where BOC incorporation yielded a full-length, active Cas9 only after BOC exposure, demonstrating conditional protein activation.
Ranked Citations
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