PA Subunit Polypeptide Fragments for Influenza Endonuclease Inhibition
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Solution Overview
Problem
Current antiviral medications for Influenza lack effective targets and are hindered by rapid development of resistant mutants, necessitating new compounds that target the viral RNA-dependent RNA polymerase's endonuclease activity, particularly the PA subunit within the Orthomyxoviridae family.
Innovation Solution
Development of polypeptide fragments comprising the amino-terminal region of the PA subunit with endonuclease activity, enabling high-resolution structural data and computational methods for identifying compounds that inhibit the endonucleolytic site, facilitating the design of therapeutic agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antiviral medications target existing viral proteins (neuraminidase, M2, RNA polymerase complex), then antiviral activity is achieved, but rapid development of resistant mutants occurs and side effects arise
Solution Approach 1:
The patent divides the RNA-dependent RNA polymerase into separate functional subunits (PA, PB1, PB2) and identifies that endonuclease activity resides specifically in the PA subunit. This segmentation allows for targeted inhibition of the endonuclease function without affecting other viral proteins, thereby reducing resistance development and side effects while maintaining antiviral activity.
2Reliability
If existing antiviral compounds are used (amantadine, rimantadine, ribavirin), then some therapeutic effect is achieved, but severe side effects occur and rapid resistance develops
Solution Approach 1:
The patent extracts the endonuclease function from the complete RNA-dependent RNA polymerase complex and identifies it as residing in the PA subunit. By targeting this specific extracted function with compounds that bind to the PA subunit's endonuclease active site, the invention achieves therapeutic effect while avoiding the severe side effects associated with broader-spectrum antivirals like ribavirin.
3Reliability
If the complete RNA-dependent RNA polymerase complex is targeted, then endonuclease activity can be inhibited, but structural complexity and difficulty in obtaining high-resolution data increase
Solution Approach 1:
The patent segments the RNA-dependent RNA polymerase complex into individual subunits and demonstrates that the endonuclease activity is contained within the PA subunit alone. This segmentation simplifies the target from a multi-subunit complex to a single polypeptide chain, enabling high-resolution structural determination through crystallography and facilitating rational drug design.
Data Source
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AI summary
The present invention relates to polypeptide fragments comprising an amino-terminal fragment of the PA subunit of a viral RNA-dependent RNA polymerase or variants thereof possessing endonuclease activity, wherein said PA subunit is from a virus belonging to the Orthomyxoviridae family. This invention also relates to (i) crystals of the polypeptide fragments which are suitable for structure determination of said polypeptide fragments using X-ray crystallography and (ii) computational methods using the structural coordinates of said polypeptide to screen for and design compounds that modulate, preferably inhibit the endonucleolytically active site within the polypeptide fragment. In addition, this invention relates to methods identifying compounds that bind to the PA polypeptide fragments possessing endonuclease activity and preferably inhibit said endonucleolytic activity, preferably in a high throughput setting. This invention also relates to compounds and pharmaceutical compositions comprising the identified compounds for the treatment of disease conditions due to viral infections caused by viruses of the Orthomyxoviridae family.