In Silico HECT E3-Ligase Inhibitor Screening via a Cryptic Cavity
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Solution Overview
Problem
Current computational approaches struggle to identify inhibitors for E3-ligases due to the absence of an active-site pocket, limiting the development of specific inhibitors for therapeutic targets like SMURF1, which is implicated in diseases such as pulmonary arterial hypertension (PAH) and other disorders.
Innovation Solution
An in silico method is employed to identify small molecule allosteric inhibitors that bind to a cryptic cavity distinct from the catalytic site of SMURF1, inducing allosteric changes by elongating the αH10 helix and shortening the glycine-hinge domain to inhibit catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If computational approaches are used to identify inhibitors, then high-throughput screening efficiency is improved, but the absence of an active-site pocket in E3-ligases prevents effective inhibitor binding and identification
Solution Approach 1:
Instead of attempting to bind inhibitors to the catalytic site (the conventional approach), the patent inverts the strategy by targeting an allosteric site located in the αH10 helix region. This inversion allows computational screening to succeed because the allosteric site provides a definable binding pocket that small molecules can occupy, thereby resolving the contradiction between high-throughput screening efficiency and inhibitor identification feasibility
Solution Approach 2:
The patent introduces an intermediary mechanism where allosteric binding at the αH10 helix induces conformational changes that propagate to the catalytic site, ultimately inhibiting enzymatic activity. This intermediary allosteric site serves as a bridge that allows small molecules to exert inhibitory effects despite the absence of a traditional active-site pocket, enabling both computational screening and effective inhibition
2Reliability
If protein structure snapshots of stable conformations are used, then structural analysis reliability is improved, but transient pockets and cavities are overlooked
Solution Approach 1:
The patent applies dynamics by recognizing and targeting the allosteric site in the αH10 helix region, which is a dynamic element that undergoes conformational changes during catalysis. By focusing on this dynamic region rather than static stable conformations, the method captures transient structural features that are essential for inhibitor binding, thereby preventing information loss while maintaining structural analysis reliability
Solution Approach 2:
The patent performs preliminary identification of the allosteric site in the αH10 helix region before conducting high-throughput screening. This preliminary action of identifying the dynamic allosteric pocket allows subsequent computational screening to effectively target transient features, resolving the contradiction between relying on stable conformation snapshots and capturing transient pocket information
Data Source
AI summary
The disclosure relates to methods for predicting allosteric inhibition of homologous to E6AP C-terminus (HECT) E3-ligases. The methods include in silico approaches for identifying small molecule allosteric inhibitors by threading amino acid sequences of target HECT ligases onto a template protein structure in its inhibited state, such as SMURF1, which comprises a cryptic allosteric cavity remote from the catalytic site and a glycine-hinge domain. The disclosure also enables screening and prediction of small molecule candidates capable of inducing allosteric changes, including elongation of the αH10 helix and shortening of the glycine-hinge domain, thereby restraining motion, essential for catalysis. The disclosed methods additionally provide validation of the predictions through structural and biochemical assays.