Variant Activin IIB Receptor Polypeptides Reducing Protein Aggregation
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Solution Overview
Problem
Current protein therapeutics for TGF-β related disorders face challenges such as protein aggregation during expression and purification, which affects manufacturability and efficacy, and there is a need for molecules that can bind multiple ligands while minimizing aggregation.
Innovation Solution
Development of a pharmaceutical composition comprising a variant activin IIB receptor polypeptide (vActRIIB) with specific amino acid substitutions at positions 28 and 40, capable of binding myostatin, activin A, or GDF-11, which reduces aggregation and improves manufacturability, combined with a chemotherapeutic agent for treating various disorders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type activin IIB receptor polypeptide is used, then binding activity to myostatin, activin A, and GDF-11 is achieved, but protein aggregation occurs during expression and purification
Solution Approach 1:
The patent applies parameter changes by substituting specific amino acid residues (positions 28, 40, and 64) in the activin IIB receptor polypeptide sequence. These sequence modifications alter the physical-chemical properties of the protein, reducing its tendency to aggregate during expression and purification while preserving its ability to bind myostatin, activin A, and GDF-11 ligands.
Solution Approach 2:
The invention applies local quality changes by making targeted amino acid substitutions at specific positions (28, 40, 64) within the polypeptide sequence. Rather than modifying the entire protein, localized changes are made to critical regions that influence aggregation propensity while maintaining overall binding function.
2Adaptability or versatility
If multiple TGF-β ligands are targeted simultaneously, then therapeutic effectiveness is improved, but protein stability and manufacturability are compromised
Solution Approach 1:
The patent creates a universal receptor polypeptide that can bind multiple TGF-β family ligands (myostatin, activin A, GDF-11) simultaneously. The modified activin IIB receptor retains its natural broad ligand specificity while the amino acid substitutions enhance protein stability and reduce aggregation, enabling the single molecule to perform multiple therapeutic functions.
3Productivity
If high levels of protein are produced during cell culture, then manufacturing efficiency is improved, but aggregation increases
Solution Approach 1:
The amino acid substitutions at positions 28, 40, and 64 fundamentally change the aggregation parameters of the protein. These sequence modifications reduce hydrophobic interactions and improve solubility, allowing the protein to be produced at high concentrations during cell culture without forming aggregates, thus enabling scalable manufacturing.
Data Source
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AI summary
The present invention provides variant activin IIB soluble receptor polypeptides and proteins capable of binding and inhibiting the activities of activin A, myostatin, or GDF-11. The present invention also provides polynucleotides, vectors and host cells capable of producing the variant polypeptides and proteins. Compositions and methods for treating muscle-wasting and other diseases and disorders are also provided.