Engineered CGL Enzymes for Cystinuria Stone Prevention
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Solution Overview
Problem
Current therapies for cystinuria are limited by significant adverse effects and fail to effectively prevent cystine stone formation in the kidney and urinary tract, as they only partially reduce circulating cystine levels.
Innovation Solution
Engineered primate cystathionine-gamma-lyase (CGL) enzymes with modified amino acid sequences are developed to efficiently degrade both L-cystine and L-cysteine, reducing their levels in the serum and preventing stone formation, while being designed to minimize immunogenicity and toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing therapies are used to reduce circulating cystine levels, then cystine stone formation is partially prevented, but significant adverse effects occur
Solution Approach 1:
The patent modifies the enzymatic parameters of cystathionine-gamma-lyase through amino acid mutations (e.g., at positions 51, 55, 59, 91, 163, 189, 193, 200, 234, 311, 336, 339, and/or 353) to enhance catalytic activity and substrate specificity. This results in an enzyme with dramatically improved kcat and lowered KM for cystine and cysteine degradation, enabling effective cystine reduction without the adverse effects of conventional therapies
Solution Approach 2:
The patent uses human or primate CGL enzyme sequences as templates to create engineered variants that replicate the beneficial enzymatic activity while minimizing immunogenicity. By copying and optimizing the natural enzyme sequence rather than using foreign proteins, the therapy achieves high catalytic efficiency with reduced adverse immune responses
2Productivity
If non-human enzyme therapeutics are used, then cystine degradation activity is achieved, but immunogenicity and adverse responses increase
Solution Approach 1:
The patent modifies specific amino acid positions in the enzyme sequence (such as positions 51, 55, 59, 91, 163, 189, 193, 200, 234, 311, 336, 339, and/or 353) to optimize the enzyme's catalytic properties and substrate binding. These parameter changes result in enhanced cystine and cysteine degradation activity while maintaining human sequence identity to reduce immunogenicity
Solution Approach 2:
The patent applies localized modifications to specific regions of the enzyme protein while maintaining the overall human sequence architecture. By making targeted changes at specific positions rather than using entirely foreign sequences, the enzyme achieves optimized local catalytic function while preserving global biocompatibility and low immunogenicity
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 modified CGL enzymes significantly reduce serum cystine levels, preventing cystine stone formation without the adverse effects associated with existing treatments, offering a superior therapeutic regimen for cystinuria patients.
Implementation Method 1
the native enzyme was engineered by modifying selected amino acids, which modifications result in an enzyme having dramatically improved enzymatic properties
Implementation Method 2
engineered human CGL enzyme that efficiently converts cystine to cysteine-persulfide, which subsequently decays to free cysteine and H2S
Data Source
AI summary
Methods and compositions related to the engineering of a protein with L-cyst(e)ine degrading enzyme activity are described. For example, disclosed are modified cystathionine-γ-lyases comprising one or more amino acid substitutions and capable of degrading L-cyst(e)ine. Furthermore, compositions and methods are provided for the treatment of cystinuria using the disclosed modified enzymes or nucleic acids encoding said enzymes.