ShK Peptide N-Terminal Extensions for Kv1.3 Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Kv1.3 channel blockers, such as ShK peptide, lack selectivity for Kv1.3 over Kv1.1 channels, posing risks of cardiac and neuro-toxicity, especially in autoimmune diseases like multiple sclerosis where the blood-brain barrier is compromised.
Innovation Solution
Development of ShK analogues with novel N-terminal tetrapeptide extensions, like EWSS, which enhance selectivity for Kv1.3 channels through specific amino acid sequences that form stable interactions with channel residues, reducing affinity for Kv1.1 channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ShK peptide is used to block Kv1.3 channels, then proliferation of T EM cells is suppressed and therapeutic effect is improved, but selectivity for Kv1.3 over Kv1.1 is lost leading to cardiac and neuro-toxicity
Solution Approach 1:
The patent applies local quality by modifying specific local regions of the ShK peptide structure - specifically adding N-terminal extensions (such as EWSS tetrapeptide) and making targeted amino acid substitutions (like E1D, I4L, S10R) while keeping the core ShK sequence intact. These localized modifications enhance selectivity for Kv1.3 channels over Kv1.1 channels, thereby reducing cardiac and neuro-toxicity while preserving the therapeutic effect of suppressing T EM cell proliferation.
2Reliability
If N-terminal extensions are added to ShK analogue, then selectivity for Kv1.3 channels is enhanced, but molecular weight and complexity increase
Solution Approach 1:
The patent applies segmentation by dividing the ShK analogue into distinct functional segments: the core ShK sequence (residues 1-35) that provides the fundamental channel-blocking activity, and the N-terminal extension segment (such as EWSS residues -4 to -1) that provides selectivity enhancement. This segmentation allows each part to fulfill its specific function independently, with the extension segment being optimally sized to provide selectivity without excessive complexity.
Solution Approach 2:
The patent applies partial action by adding only the minimal necessary N-terminal extension (typically 3-5 amino acid residues) to achieve the desired selectivity enhancement. This partial modification is sufficient to distinguish Kv1.3 from Kv1.1 channels through specific interactions (such as the interaction between the extended N-terminal residues and extracellular loop regions of Kv1.3), without adding excessive complexity or size to the peptide structure.
Data Source
Figure 1A~1D
Figure 2
Figure 3A~3B
AI summary
Novel analogues of the sea anemone Stichodactyla helianthus toxin ShK, and their use as, for example, therapeutic agents for treating autoimmune diseases are disclosed. The analogues comprise a ShK toxin polypeptide and an N-terminal extension comprising an amino acid sequence according to formula (I): wherein X-4 is D, E or other negatively-charged amino acid or derivative thereof, X-3 is E, I, L, S, V, W or a tryptophan derivative, X-2 is any amino acid, X-1 is any amino acid, a is absent or a first additional moiety, and b is absent or a second additional moiety.