Chimeric Protease Inhibitor Covalent Binding hK2
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Solution Overview
Problem
Current protease inhibitors, particularly those targeting human kallikrein 2 (hK2), often exhibit reversible binding, which can lead to the restoration of protease activity, and existing inhibitors are not specific enough to effectively inhibit hK2 in a therapeutic context, especially in conditions like prostate cancer.
Innovation Solution
Development of chimeric inhibitor proteins comprising an inhibiting polypeptidic sequence and a polypeptidic sequence specific to a substrate-enzyme interaction site, specifically designed to form covalent complexes with hK2, utilizing modified reactive serpin loop sequences to enhance specificity and stability of inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protease inhibitors are used, then protease activity is inhibited, but the binding is reversible leading to restoration of protease activity
Solution Approach 1:
The patent modifies the reactive serpin loop sequence parameters to change the binding mode from reversible to covalent. By altering the amino acid sequence in the reactive site loop, the inhibitor forms a stable covalent bond with the protease active site, preventing reversal and ensuring durable inhibition.
Solution Approach 2:
The patent creates chimeric inhibitor proteins that combine the inhibitory serpin domain with substrate-enzyme interaction sites. This composite structure integrates the covalent binding capability of modified serpins with the specificity of substrate recognition sequences, achieving both durable binding and target specificity.
2Reliability
If existing protease inhibitors are used, then protease activity is reduced, but the inhibitors are not specific enough to effectively inhibit hK2
Solution Approach 1:
The patent introduces substrate-enzyme interaction sites specifically designed for hK2 recognition into the inhibitor protein. This local modification at the binding interface provides high specificity for hK2 while maintaining the covalent inhibition mechanism, ensuring the inhibitor effectively targets only the desired protease.
Solution Approach 2:
The inhibitor protein is divided into functional segments: the inhibitory serpin domain that provides covalent binding and the substrate-enzyme interaction site that provides specificity. This segmentation allows each domain to optimize its function independently, with the serpin domain ensuring durable inhibition and the interaction site ensuring target specificity.
3Reliability
If chimeric inhibitor proteins with modified reactive serpin loop sequences are used, then specificity and stability of inhibition are enhanced, but the protein structure becomes more complex
Solution Approach 1:
The patent extracts and modifies only the critical reactive serpin loop region while maintaining the overall serpin fold structure. By focusing modifications on the small reactive site loop rather than the entire protein, the patent achieves enhanced specificity and stability without proportionally increasing overall structural complexity.
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 chimeric inhibitors demonstrate high specificity and rapid formation of covalent complexes with hK2, achieving complete inhibition within minutes, with some variants showing no activity against other tested proteases, thereby providing a long-lasting and effective therapeutic solution for hK2-related disorders.
Implementation Method 1
Following the binding to the enzyme and cleavage of the P1-P1′ scissile bond of the RSL, a covalent complex is formed
Data Source
AI summary
The present invention relates to a chimeric inhibitor protein of a protease comprising an inhibiting polypeptidic sequence and at least one polypeptidic sequence of a substrate-enzyme interaction site specific for a protease. Other objects of the invention are to provide a purified and isolated DNA sequence encoding the chimeric inhibitor protein of a protease, an expression vector characterized in that it comprises said purified and isolated DNA sequence, a eukaryotic or prokaryotic host cell transformed with this expression vector and a method of producing a chimeric inhibitor protein.