Chimeric Peptide cAMP Sensor via FRET
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Solution Overview
Problem
Current methods for determining cyclic AMP (cAMP) levels in vivo are limited by sensitivity, affinity, and detectability, and existing cAMP sensors interfere with intracellular processes or require radioactive materials, making real-time optical cAMP determination challenging.
Innovation Solution
A chimeric peptide with a single cAMP binding site flanked by detectable labels at the carboxy and amino terminus, allowing for direct and sensitive detection of cAMP concentrations in vitro and in vivo through fluorescence resonance energy transfer (FRET) without catalytic activity or radioactive compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional cAMP sensors are used for in vivo detection, then cAMP levels can be measured, but the sensors interfere with intracellular processes and require radioactive materials
Solution Approach 1:
The invention extracts only the cAMP binding domain from the full-length adenylyl cyclase protein, creating a minimized sensor that retains cAMP binding capability but lacks catalytic activity. This extracted domain is fused to fluorescent proteins to create a non-interfering detection tool that measures cAMP without disrupting cellular processes.
Solution Approach 2:
The invention replaces radioactive detection methods with fluorescence resonance energy transfer (FRET) detection. The chimeric peptide contains fluorescent protein domains that transfer energy when cAMP binds, allowing optical detection instead of radioactive labeling, thereby eliminating harmful radiation while maintaining detection sensitivity.
2Quantity of substance
If existing cAMP detection methods are used, then cAMP concentration can be determined, but the methods are limited by sensitivity and affinity
Solution Approach 1:
The invention creates a composite chimeric peptide structure combining the cAMP binding domain with fluorescent protein domains (CFP and YFP). This composite structure maintains the high affinity and specificity of the natural cAMP binding domain while adding optical detection capabilities, thereby improving sensitivity without losing binding precision.
3Loss of time
If real-time optical cAMP determination is implemented, then temporal and spatial resolution is improved, but device complexity increases
Solution Approach 1:
The chimeric peptide performs self-detection through intrinsic FRET properties. When cAMP binds to the binding domain, it induces a conformational change that alters the distance between the fluorescent protein domains, automatically generating a detectable fluorescence signal without requiring external complex detection machinery.
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
The chimeric peptide provides high temporal and spatial resolution for cAMP detection, enabling real-time monitoring without interfering with cellular processes and eliminating the need for radioactive materials, thus overcoming the limitations of previous cAMP detection systems.
Implementation Method 1
allowing for direct and sensitive detection of cAMP concentrations in vitro and in vivo through fluorescence resonance energy transfer (FRET)
Data Source
AI summary
Described is a chimeric peptide, comprising, in order, (a) a first detectable label (b) a cAMP binding moiety having only one cAMP binding site and (c) a second detectable label least two detectable labels is describe. The chimeric peptide is useful for direct determination of cAMP concentration in vitro and/or in vivo. Also described are nucleic acids encoding the chimeric peptide, methods of making and modifying the chimeric peptide, a method for determining the cAMP concentration, and kits.