Beta-lactone probes for selective PBP labeling
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Solution Overview
Problem
Current methods lack the ability to selectively target and detect individual penicillin-binding proteins (PBPs) in bacteria, hindering the understanding of their discrete roles in peptidoglycan synthesis and antibiotic resistance, particularly in Streptococcus pneumoniae and Escherichia coli.
Innovation Solution
Development of β-lactone-based conjugates that selectively bind to PBPs, allowing for their labeling and visualization, enabling the differentiation of individual PBP homologs and their activity states within bacterial cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If radiolabeled penicillin is used to profile PBP activity, then information about catalytic activity state is obtained, but in vivo visualization is prevented and discrete characterization of individual PBPs is impossible
Solution Approach 1:
The patent changes the detection parameter from radioactivity to fluorescence, enabling in vivo visualization while maintaining PBP activity state information. The fluorophore-conjugated penicillin analogs allow optical detection in living cells, resolving the contradiction between obtaining activity information and enabling visualization.
Solution Approach 2:
The patent segments the detection capability by using multiple fluorophores with different emission wavelengths to label different PBP classes. This allows discrete characterization of individual PBP homologs (Class A, B, and C PBPs) simultaneously in vivo, overcoming the limitation of non-specific labeling.
2Ease of operation
If fluorophore-conjugated penicillin V analog is used, then in vivo visualization is enabled, but selective targeting of individual PBP homologs is lost
Solution Approach 1:
The patent applies local quality by designing fluorophore-conjugated penicillin analogs with specific side chain modifications that confer selectivity for particular PBP classes. Different fluorophore-conjugated compounds are used to target different PBP homologs, enabling both visualization and selective discrimination.
3Measurement precision
If artificial fusion constructs are used to study single PBPs, then discrete PBP function can be assessed, but protein concentration, function, or localization is perturbed
Solution Approach 1:
The patent uses fluorophore-conjugated penicillin analogs as intermediary molecules that bind to and label native PBPs in their physiological context. This indirect labeling approach avoids the need for artificial fusion constructs, maintaining the natural state of the proteins while enabling discrete function assessment.
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
Enables the selective labeling and visualization of specific PBPs, facilitating a deeper understanding of their roles in peptidoglycan synthesis and antibiotic resistance, and providing tools for investigating bacterial cell wall biosynthesis and antibiotic action.
Implementation Method 1
All PBPs possess a catalytic serine in their peptidase domain, which is required for substrate turnover and is the site for covalent modification by the β-lactam antibiotics
Implementation Method 2
β-lactone-based conjugates that selectively bind to PBPs, allowing for their labeling and visualization
Data Source
AI summary
The invention provides a compound of formula I:or a salt thereof, wherein R1, R2, R3, R4, L1, L2 and Y have any of the values described in the specification, as well as compositions comprising a compound of formula I. The compounds are useful for labeling penicillin-binding proteins (PBPs).