Circular Permutation of Protein Ligands for Receptor Modulation
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Solution Overview
Problem
Current monoclonal antibody approaches for inhibiting ligand-receptor interactions are limited by high manufacturing costs, large size, poor tissue penetration, and undesirable side effects, and are primarily designed to inhibit rather than enhance signaling pathways, necessitating the development of alternative protein engineering strategies for therapeutic applications.
Innovation Solution
The creation of fusion polypeptides through circular permutation of protein ligands, which generates new amino and carboxy termini while retaining binding affinity and specificity, allowing for the design of agonists, superagonists, or antagonists that can be used to modulate signaling pathways effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibody approaches are used to inhibit ligand-receptor functions, then therapeutic inhibition can be achieved, but manufacturing costs are high, size is large, tissue penetration is limited, and side effects occur
Solution Approach 1:
The patent replaces expensive monoclonal antibodies with small protein ligands that are cheaper to manufacture. These ligands, while smaller and potentially shorter-lived in circulation, achieve therapeutic inhibition through high-affinity binding to receptors, eliminating the need for costly antibody production while maintaining efficacy.
Solution Approach 2:
The patent extracts and utilizes only the essential ligand portion needed for receptor binding, discarding the large antibody structure. By focusing on the minimal functional unit (the ligand itself or a simplified version), the invention achieves therapeutic effect with a much smaller, cheaper, and more tissue-penetrant molecule.
2Reliability
If monoclonal antibody approaches are used, then therapeutic inhibition can be achieved, but the size is large leading to limited tissue penetration
Solution Approach 1:
The patent extracts the essential binding function from the large antibody molecule, using only the small ligand portion that is necessary for receptor interaction. This extracted ligand maintains therapeutic efficacy while being small enough to penetrate tissues effectively.
Solution Approach 2:
The patent employs small ligand molecules that are much smaller than antibodies. These smaller molecules can penetrate tissues more easily and achieve therapeutic inhibition through high-affinity binding, compensating for their smaller size with enhanced binding strength.
3Device complexity
If traditional ligand structures are used for fusion polypeptide construction, then simplicity is maintained, but the binding affinity and activity are diminished
Solution Approach 1:
The patent applies circular permutation to change the topological parameters of the ligand structure, creating new N- and C-termini at strategic locations. This structural reparameterization allows for optimized fusion polypeptide construction while preserving or enhancing binding affinity, as the new termini can be positioned to favorably interact with the receptor or fusion partner.
4Reliability
If circular permutation is applied to create new termini, then binding affinity and activity are enhanced, but the protein structure is reordered
Solution Approach 1:
The patent deliberately changes the topological parameters of the protein by applying circular permutation. This reorders the sequence while creating new termini at locations that enhance binding affinity and facilitate fusion polypeptide construction. The secondary structure and activity are preserved despite the sequence reorganization.
Data Source
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AI summary
The present invention provides fusion polypeptides comprising polypeptide ligands that are modified by circular permutation and fused to at least one polypeptide fusion partner wherein such fusion polypeptides have new, improved or enhanced biological functions or activities. Such improvements include, but are not limited to, increased binding affinity, increased activity, increased agonist activity (super agonist), antagonist activity, increased accessibility, increased flexibility of the active site, increased stability, broader and/or changed substrate specificity, and combinations thereof.