Recombinant Polypeptide Reporter for Safe Protease Measurement
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Solution Overview
Problem
Current methods for measuring protease activities, particularly those of potent neurotoxins like botulinum and tetanus toxins, are unsafe and inaccurate due to their strong toxicity and low concentrations.
Innovation Solution
A recombinant polynucleotide encoding a polypeptide with a reporter moiety, a substrate moiety, and a destabilization moiety is used, which includes a cleavage site recognized by proteases, allowing for safe and accurate measurement of protease activity through detectable signal emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to measure protease activities of neurotoxins, then measurement can be performed, but the measurement is unsafe and inaccurate due to strong toxicity and low concentrations
Solution Approach 1:
The patent introduces a reporter polypeptide as an intermediary substance that indirectly detects protease activity. The reporter polypeptide contains a substrate moiety with a cleavage site recognized by proteases, a destabilization moiety that promotes degradation, and a reporter moiety that emits detectable signals. This intermediary system allows safe and accurate measurement of neurotoxin activity without direct exposure to toxic substances.
Solution Approach 2:
The patent changes the measurement parameter from direct toxin detection to indirect signal emission detection. By monitoring the emission intensity of the reporter moiety, which changes in response to protease-mediated cleavage and destabilization, the system achieves high measurement sensitivity and accuracy for low-concentration neurotoxins without requiring direct handling of toxic substances.
2Measurement precision
If a polypeptide with destabilization moiety is used to enhance signal emission, then measurement precision is improved, but the polypeptide becomes more sensitive to protease degradation
Solution Approach 1:
The patent employs a dynamic destabilization mechanism where the destabilization moiety (e.g., PEST sequence or ubiquitin-like domain) actively promotes time-dependent degradation of the reporter polypeptide. This dynamic instability enhances the signal change upon protease cleavage, improving measurement precision while the controlled nature of degradation maintains sufficient polypeptide stability for reliable detection.
Solution Approach 2:
The reporter polypeptide is segmented into distinct functional domains: substrate moiety, destabilization moiety, and reporter moiety. This segmentation allows each domain to perform its specific function independently - the substrate moiety provides protease recognition, the destabilization moiety controls degradation rate, and the reporter moiety provides detectable signal - thereby achieving both high measurement precision and controlled stability.
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
This approach enables precise and safe determination of protease activities by enhancing signal emission when the polypeptide is cleaved by proteases, facilitating the measurement of neurotoxin levels without cellular damage.
Implementation Method 1
The reporter moiety is a fluorescence protein
Implementation Method 2
The reporter moiety is luciferase
Implementation Method 3
The reporter moiety is alkaline phosphatase, β-galactosidase, chloramphenicol acetyltransferase, or β-glucuronidase
Implementation Method 4
a destabilization moiety; and a substrate moiety operatively linking the reporter moiety to the destabilization moiety, wherein the substrate moiety includes a cleavage site of protease activity
Data Source
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AI summary
Provided are a recombinant polynucleotide coding for polypeptide comprising a reporter moiety, a substrate moiety, and a destabilizing moiety, a host cell comprising same and a method for measuring a protease level by means of same.