FAP Detection Peptide Probes Specificity and Stability
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Solution Overview
Problem
Existing probes for detecting fibroblast activation protein-α (FAP) lack specificity over related enzymes like prolyl oligopeptidase (PREP) and are susceptible to degradation in inflammatory environments.
Innovation Solution
Development of peptide constructs specifically cleavable by FAP, which upon cleavage generate a detectable signal, ensuring specificity over other related enzymes and resistance to degradation in inflammatory conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing peptide sequences are used for FAP detection, then FAP detection capability is achieved, but specificity over related enzymes like PREP deteriorates
Solution Approach 1:
The patent applies local quality by introducing a D-amino acid at a specific position within the peptide sequence. This localized modification at the P2 position (four residues from the scissile bond) creates stereospecific recognition that distinguishes FAP from PREP, while maintaining overall sequence functionality for FAP detection.
Solution Approach 2:
The patent changes the stereochemical parameter of the amino acid at position P2 from L-configuration to D-configuration. This parameter change fundamentally alters the peptide's interaction with proteases, enabling selective cleavage by FAP while resisting cleavage by PREP, thus resolving the specificity issue.
2Measurement precision
If existing peptide constructs are used in inflammatory environments, then FAP detection is attempted, but degradation by other proteases increases
Solution Approach 1:
The introduction of a D-amino acid at the P2 position creates a localized stereospecific feature that protects the peptide from degradation by L-protease prevalent in inflammatory environments, while maintaining susceptibility to FAP which can process D-containing sequences.
Solution Approach 2:
The D-amino acid modification serves as a preliminary protective measure against non-specific proteolytic degradation. By pre-configuring the peptide with stereochemical resistance to L-proteases before exposure to inflammatory environments, the construct maintains integrity until specific FAP-mediated cleavage occurs.
3Ease of manufacture
If standard amino acid sequences are used, then ease of synthesis is maintained, but selectivity over related peptidases deteriorates
Solution Approach 1:
The patent changes the stereochemical parameter of a single amino acid residue from L to D configuration. This minimal parameter change maintains synthetic feasibility using standard solid-phase peptide synthesis methodologies while dramatically improving enzyme selectivity through stereospecific recognition by FAP.
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 peptide constructs provide selective detection of FAP activity or expression, overcoming the limitations of existing probes by maintaining specificity and stability in challenging environments.
Implementation Method 1
a peptide construct that is selectively cleavable by FAP... comprising a FAP cleavable peptide... wherein the construct cleavable by FAP comprises of the sequence
Data Source
AI summary
The present disclosure relates to the development of novel constructs that are specifically cleaved by fibroblast activation protein-α (FAP) and uses thereof in assays for detecting FAP. Particular constructs include a fluorescence resonance energy transfer (FRET) probe comprising a fluorescent moiety and a quencher moiety attached to a FAP cleavable peptide sequence and optionally including a solubilising moiety, which may be a polyethylene glycol (PEG) derivative.