Riboswitch Analysis via smFRET and SHAPE Probing
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Solution Overview
Problem
Current understanding of preQ1-II and TPP riboswitches lacks high-resolution structures of both free and ligand-bound forms, particularly for class II riboswitches, hindering insights into ligand recognition and gene regulation mechanisms.
Innovation Solution
The development of isolated riboswitches with attached fluorophores for single-molecule fluorescence resonance energy transfer (smFRET) imaging, allowing for the detection of structural changes and ligand binding dynamics, and the use of methods to identify compounds interfering with riboswitch function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution structures of free and ligand-bound riboswitches are obtained, then insights into ligand recognition and gene regulation mechanisms are improved, but the complexity and difficulty of structural determination increase
Solution Approach 1:
The patent segments the riboswitch structure into distinct domains (aptamer domain and expression platform) and uses separate probing approaches for each region. The aptamer domain is studied for ligand binding while the expression platform is analyzed for structural changes, allowing high-resolution characterization without overwhelming complexity
Solution Approach 2:
The patent employs SHAPE reagents as intermediaries to probe RNA structure. These chemical probes act as mediators that selectively modify flexible versus structured regions of the riboswitch, translating complex three-dimensional structural information into detectable chemical modification patterns that can be analyzed
2Loss of information
If detailed folding and ligand recognition processes are analyzed, then understanding of riboswitch mechanisms is improved, but the time and resources required for analysis increase
Solution Approach 1:
The patent performs preliminary SHAPE probing under different conditions (with and without ligand, at different temperatures) to pre-map the structural states of the riboswitch. This preliminary structural characterization allows subsequent kinetic and mechanistic studies to focus on specific transitions rather than进行全面 analysis from scratch
Solution Approach 2:
The patent uses periodic temperature cycling and ligand addition/removal cycles to induce reversible structural transitions in the riboswitch. By repeatedly cycling between folded and unfolded states, the patent captures dynamic folding intermediates and ligand recognition events that would be difficult to observe in static snapshots
3Adaptability or versatility
If compounds interfering with riboswitch function are identified, then potential antibiotic candidates are discovered, but the screening complexity and false positive rate increase
Solution Approach 1:
The patent replaces traditional biochemical assays with fluorescence-based detection methods. Fluorophore-labeled riboswitches enable real-time, sensitive detection of conformational changes induced by compound binding, providing a more reliable and automated screening platform that reduces manual intervention and subjective interpretation
Solution Approach 2:
The patent implements a feedback mechanism where SHAPE probing data from compound-treated samples is directly compared to control samples to identify true positives. The method uses differential modification patterns as feedback signals to distinguish compounds that genuinely affect riboswitch structure from those that do not, reducing false positives
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
Provides detailed insights into the folding and ligand recognition processes of preQ1-II and TPP riboswitches, enabling the identification of compounds that modulate their activity and potentially serve as antibiotics.
Implementation Method 1
single-molecule fluorescence resonance energy transfer (smFRET) imaging, allowing for the detection of structural changes and ligand binding dynamics
Data Source
AI summary
We provide isolated TPP and preQ1 class II riboswitches which are labelled for FRET studies of ribosome function. The riboswitches may be used in assays to determine riboswitch function, and to test the activity of compounds in modulating riboswitch function.