Cyclic Peptide Aβ Aggregation Inhibitor Design
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Solution Overview
Problem
Current Aβ aggregation inhibitors, such as the pentapeptide L-[Lys-Leu-Val-Phe-Phe, exhibit weak inhibitory activity and poor metabolic stability, making them ineffective as preventive or therapeutic drugs for Alzheimer's disease.
Innovation Solution
A cyclic peptide with specific amino acid substitutions and aromatic groups is developed, which exhibits superior inhibitory activity against Aβ aggregation and improved metabolic stability, forming the basis for a drug to prevent or treat Alzheimer's disease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pentapeptide L-[Lys-Leu-Val-Phe-Phe] is used as an Aβ aggregation inhibitor, then it can bind to Aβ peptide, but it exhibits very weak inhibitory activity and poor metabolic stability
Solution Approach 1:
The patent applies parameter changes by cyclizing the pentapeptide structure and substituting specific amino acid residues (Phe at positions 4 and 5 with aromatic amino acids having lipophilic side chains). These structural parameter changes dramatically improve both the inhibitory activity against Aβ aggregation and the metabolic stability, transforming a weak linear peptide into a potent cyclic peptide drug candidate with enhanced resistance to proteolytic degradation
Solution Approach 2:
The patent creates a composite structure by combining the core pentapeptide sequence with cyclic constraints and aromatic amino acid substitutions. This composite approach integrates multiple functional elements: the cyclic structure provides metabolic stability, while the aromatic substitutions enhance binding affinity and inhibitory activity, resulting in a superior therapeutic agent
2Reliability
If a cyclic peptide is formed through cyclization of the pentapeptide, then inhibitory activity for Aβ aggregation is markedly improved, but the structural complexity increases
Solution Approach 1:
The patent employs parameter changes by introducing a cyclic constraint into the pentapeptide structure. This single structural modification fundamentally alters the peptide's conformational properties, enhancing its inhibitory activity against Aβ aggregation by marking it superior to the linear counterpart, while the complexity increase remains manageable through efficient synthesis methods
3Reliability
If aromatic amino acid residues are substituted into the cyclic peptide, then inhibitory activity for Aβ aggregation is further enhanced, but the synthesis difficulty increases
Solution Approach 1:
The patent applies parameter changes by substituting aromatic amino acid residues (with lipophilic side chains) at specific positions within the cyclic pentapeptide structure. These substitutions further enhance the inhibitory activity beyond what is achieved by cyclization alone. The increased synthesis difficulty is offset by the use of standard solid-phase peptide synthesis methodologies, making the compound feasible for pharmaceutical development
Data Source
AI summary
Provided is a novel compound which has excellent inhibitory activity for Aβ aggregation, and which is useful as a drug. A cyclic peptide or a salt thereof, the cyclic peptide having an amino acid sequence represented by the following formula (1): X-Leu-Val-Y1-Y2 (1) (wherein X is Lys, Arg, His, Ala, Gly, Ser, or Thr; and Y1 and Y2, which are identical to or different from each other, each represent a group represented by the following formula (2) : (wherein Ar1 represents an aromatic hydrocarbon group or an aromatic heterocyclic group (the aromatic hydrocarbon group or the aromatic heterocyclic group may have 1 to 5 substituents selected from the group consisting of an alkyl group, a cycloalkyl group, a haloalkyl group, a halogen atom, a hydroxy group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group, and an amino group); R1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, a haloalkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group (the aromatic hydrocarbon group or the aromatic heterocyclic group may have 1 to 5 substituents selected from the group consisting of an alkyl group, a cycloalkyl group, a haloalkyl group, a halogen atom, a hydroxy group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group, and an amino group); and n is an integer from 0 to 2)), wherein the α-amino group at the amino terminus of the amino acid sequence is linked, via a peptide bond, to the carboxyl group at the carboxyl terminus of the amino acid sequence.