Recombinant AAT Mutants for Thermostability and Oxidation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current AAT drugs derived from human serum are insufficient for treating AAT deficiency, as they are not adequately tested for other respiratory disorders and have limited scalability and stability issues, particularly due to the formation of insoluble inclusion bodies when overexpressed in bacteria.
Innovation Solution
Development of a recombinant AAT with enhanced thermostability and oxidation resistance through efficient inclusion refolding and purification, along with site-specific chemical modifications such as PEGylation and fatty acid modification, to improve stability and in vivo half-life, using E. coli expression systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AAT is overexpressed in E. coli to meet large-scale manufacturing requirements, then productivity increases, but the protein forms insoluble inclusion bodies reducing manufacturing quality
Solution Approach 1:
The patent introduces point mutations (F51L, M351V, M358V) in the AAT protein sequence to change its biophysical properties. These parameter changes at the molecular level prevent inclusion body formation while maintaining high expression levels in E. coli, thus achieving both high productivity and proper protein solubility.
Solution Approach 2:
The patent applies site-specific mutations at particular amino acid positions (51, 351, 358) rather than global modifications. This local quality approach targets specific regions of the protein that are responsible for aggregation, leaving the rest of the protein structure and function intact.
2Reliability
If native AAT is used for therapy, then it provides the required antiprotease function, but it has limited stability and short in vivo half-life
Solution Approach 1:
The patent employs PEGylation (attachment of polyethylene glycol chains) and fatty acid modification to change the physical and chemical parameters of AAT. These modifications increase the hydrodynamic radius and reduce renal clearance, thereby extending in vivo half-life while preserving the antiprotease function.
3Manufacturing precision
If AAT is produced from human serum, then it ensures high purity and proper folding, but scalability is limited and costs are high
Solution Approach 1:
The patent creates recombinant copies of human AAT in E. coli expression systems. These copied proteins are genetically identical to native AAT but are produced at much larger scales through microbial fermentation, replacing the limited human serum supply chain.
4Reliability
If current AAT drugs are used, then they treat AAT deficiency, but they are not adequately tested for other respiratory disorders
Solution Approach 1:
The patent develops a universal recombinant AAT platform that can treat multiple respiratory conditions beyond AAT deficiency, including emphysema, COPD, and cystic fibrosis. The modified AAT molecules maintain their antiprotease function while gaining extended stability and half-life, making them suitable for broader therapeutic applications.
Data Source
AI summary
Provided is a new AAT triple-mutant, and methods to produce and purify the new entity. The new mutant is produced by a structure-based protein design to provide a more thermostable and oxidation-resistant agent for various pharmaceutical applications. The present invention also provides methods for E. coli expression, inclusion body refolding, and purification of the triple-mutant. Furthermore, the invention also provides methods for chemically modifying the purified drug candidate to provide a longer in vivo half-life and achieve better drug efficacy.