Cyclic Peptides Targeting Bam Complex for Gram-Negative Resistance
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Solution Overview
Problem
Gram-negative bacteria exhibit intrinsic resistance to antibacterials due to the combination of the outer membrane permeability barrier and the expression of multidrug efflux pumps, posing a challenge in anti-infective therapy.
Innovation Solution
Development of novel cyclic peptides that inhibit the folding and insertion of nascent proteins into the outer membrane, specifically targeting the Bam complex, thereby disrupting the bacterial outer membrane integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antibacterials are used against Gram-negative bacteria, then the outer membrane provides a permeability barrier that prevents drug entry, but this barrier alone is not sufficient to explain resistance since most drug molecules can equilibrate across the OM in less than a minute
Solution Approach 1:
The cyclic peptide acts as an intermediary that specifically binds to and inhibits the Bam complex, preventing the folding and insertion of outer membrane proteins. This mediation disrupts the cooperative defense mechanism between the outer membrane barrier and efflux pumps, thereby overcoming intrinsic resistance without requiring the peptide to directly penetrate the outer membrane itself.
Solution Approach 2:
The cyclic peptide performs preliminary action by inhibiting the Bam complex before the outer membrane proteins can complete their folding and insertion. This prevents the formation of functional efflux pumps and maintains the outer membrane in a state that is more permeable to antibacterial agents, thereby preemptively disrupting the resistance mechanism.
2Reliability
If multidrug efflux pumps are expressed by Gram-negative bacteria, then these pumps mediate resistance to multiple classes of antibacterials, but the cooperation between efflux pumps and the outer membrane barrier creates a more complex resistance mechanism
Solution Approach 1:
The cyclic peptide targets the Bam complex as an intermediary component in the efflux pump formation pathway. By binding to and inhibiting Bam, the peptide prevents the proper folding and insertion of efflux pump proteins into the outer membrane, thereby disrupting the efflux mechanism without needing to directly interact with the pumping action itself.
Solution Approach 2:
The cyclic peptide extracts or removes the Bam complex from its functional role in protein insertion. By specifically binding to Bam and preventing its activity, the peptide effectively takes out this critical component from the resistance mechanism, thereby disabling the cooperative defense between the outer membrane and efflux pumps.
3Reliability
If the Bam complex is targeted to inhibit folding and insertion of nascent proteins into the outer membrane, then outer membrane integrity is disrupted, but this requires specific molecular recognition and binding
Solution Approach 1:
The cyclic peptide exhibits local quality by having specific amino acid residues that are tailored for binding to particular regions of the Bam complex. This localized molecular recognition allows the peptide to specifically target Bam without affecting other outer membrane proteins, achieving selective disruption of protein insertion while maintaining overall structural specificity.
Solution Approach 2:
The cyclic peptide functions as a composite molecular structure combining multiple amino acid components with different properties (hydrophobic, hydrophilic, charged, uncharged residues) that work together to achieve specific binding to the Bam complex. This composite nature allows the peptide to simultaneously satisfy the requirements for molecular recognition and functional disruption.
Data Source
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AI summary
Provided herein are antibacterial compound peptides active against Gram-negative bacteria. In various embodiments, the compounds act by inhibition of BAM A membrane protein. Pharmaceutical compositions and methods for treatment using the compounds described herein are also provided.