Gla Domain Peptides for PtdS Targeting Below Kidney Filtration Size
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Solution Overview
Problem
Current biologic probes for targeting phosphatidylserine (PtdS) on cell membranes, such as Annexin-V, are not fully exploited in clinical applications due to their size and specificity limitations, and there is a need for improved methods to detect and treat conditions associated with PtdS expression, such as cancer and viral infections.
Innovation Solution
Development of gamma-carboxyglutamic-acid (Gla) domain peptides and polypeptides that specifically bind to PtdS on cell membranes, which can be used as diagnostic and therapeutic agents, potentially linked to therapeutic payloads like chemotherapeutics or anti-viral agents, and may include additional domains like EGF or Kringle domains for enhanced targeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Annexin-V is used as a PtdS targeting probe, then affinity for PtdS is improved, but molecular size increases above kidney filtration threshold
Solution Approach 1:
The patent extracts only the essential Gla domain from the full Annexin-V protein, removing unnecessary portions while retaining the PtdS binding capability. This results in a peptide fragment (residues 1-45 of Annexin-V) that maintains high affinity for PtdS but has reduced molecular weight below the kidney filtration threshold, enabling both diagnostic and therapeutic applications.
Solution Approach 2:
The patent segments the Annexin-V protein into functional domains, specifically isolating the Gla domain (residues 1-45) that is responsible for PtdS binding. This segmentation allows the peptide to be smaller and more suitable for clinical use while maintaining the critical binding function, and enables potential fusion with other functional domains like EGF or Kringle domains.
2Reliability
If full-length Annexin-V is used, then specificity for PtdS is improved, but ease of administration and therapeutic utility deteriorate
Solution Approach 1:
The patent extracts the minimal functional unit (Gla domain, residues 1-45) from Annexin-V that is sufficient for PtdS binding, eliminating the need to administer the entire large protein. This extracted peptide can be more easily administered and has improved pharmacokinetic properties while maintaining the specificity required for therapeutic applications.
Solution Approach 2:
The patent changes the molecular size parameter by using a peptide fragment instead of full-length protein, and can modify the amino acid sequence within the Gla domain to optimize properties such as half-life, binding affinity, and pharmacokinetics. These parameter changes make the agent more suitable for clinical administration and therapeutic use.
3Weight of moving object
If Gla domain peptides are used, then size is reduced for better kidney filtration, but affinity and specificity must be maintained
Solution Approach 1:
The patent optimizes the amino acid sequence within the Gla domain (residues 1-45 of Annexin-V) to maintain high binding affinity and specificity for PtdS despite the reduced size. The sequence has been engineered to ensure proper calcium-dependent binding while keeping the molecular weight below the kidney filtration threshold, achieving both small size and high reliability.
Solution Approach 2:
The patent creates composite targeting agents by fusing the Gla domain peptide with other functional domains such as EGF (epidermal growth factor) domains or Kringle domains. These composite molecules combine the small size and PtdS binding capability of the Gla domain with additional functions, maintaining affinity and specificity while enabling diverse therapeutic applications.
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 Gla domain peptides offer improved affinity, specificity, and size advantages over existing probes, enabling effective targeting of PtdS for diagnostic and therapeutic purposes, including cancer treatment and viral disease management.
Implementation Method 1
The Gla domain peptides offer improved affinity, specificity, and size advantages over existing probes, enabling effective targeting of PtdS for diagnostic and therapeutic purposes
Data Source
AI summary
The disclosure relates to the recombinant Gla domain proteins and their use targeting phosphatidylserine (PtdS) moieties on the surface of cells, particularly those expressing elevated levels of PtdS, such as cells undergoing apoptosis. These proteins can be linked to both diagnostic and therapeutic payloads, thereby permitting identification and treatment of cells expression elevated PtdS.