Quantum Mechanical X-Ray Diagnostic for Protein Protonation

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Solution Overview

Problem

Current methods, such as X-ray crystallography and neutron diffraction, are inadequate for accurately determining the conformation, protonation, and solvent effects of proteins in real-world conditions, limiting the ability to predict how drug molecules interact with proteins.

Innovation Solution

A diagnostic tool that combines semi-empirical quantum mechanics with X-ray crystallography, using the XModeScore method to refine protonation and tautomeric modes, providing a practical and reliable assessment of protein structure and reactivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If X-ray crystallography is used to image a target protein, then structural information is obtained, but information about epitopes, protonation, and solvent effects is insufficient

Engineering Contradiction:
Improvestructural informationVSAvoidprotonation and solvent effects
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent combines X-ray crystallography with semi-empirical quantum mechanics calculations to create a hybrid diagnostic approach. The quantum mechanical calculations complement the X-ray structural data by providing information about electron density distributions, protonation states, and solvent effects that are not directly observable by X-ray methods alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces difference electron density maps as an intermediary tool that bridges the gap between X-ray crystallographic data and quantum mechanical predictions. These difference maps highlight regions where the experimental electron density deviates from the modeled structure, revealing information about protonation states and solvent molecules.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If neutron diffraction is used to assess proteins, then accurate conformation and protonation information is obtained, but the method is extremely laborious, time-consuming and costly

Engineering Contradiction:
Improveprotonation informationVSAvoidlaborious and time-consuming
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses quantum mechanical calculations to create a computational model that replicates the information obtained from neutron diffraction experiments. By calculating difference electron density maps and comparing them with quantum mechanical predictions, the method reproduces protonation state information without requiring actual neutron diffraction experiments.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces expensive and time-consuming neutron diffraction experiments with computationally efficient semi-empirical quantum mechanics calculations. The computational approach provides comparable information about protonation states and conformation at a fraction of the time and resource cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If theoretical models are used to predict protein-ligand interactions, then predictions can be made in advance, but the unpredictable conformations and solvent effects make the models virtually impossible to use

Engineering Contradiction:
Improveadvance predictionVSAvoidpredictive accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the parameters used in theoretical models by incorporating difference electron density information and quantum mechanical calculations. This transforms the models from relying solely on atomic coordinates to using electron density distributions and quantum mechanical energy calculations, significantly improving predictive accuracy for protein-ligand interactions.

Inventive Principle:
Principle #35Parameter changes

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 tool effectively identifies the correct protonation and tautomeric states of proteins, validated by neutron diffraction, enabling accurate predictions of protein-ligand interactions and improving drug discovery processes.

Implementation Method 1

X-ray crystallography can image a target protein to an extent but cannot provide enough information about epitopes, protonation or solvent effects

Methodology Applied
Scientific EffectX-ray crystallography: X-Ray

Implementation Method 2

The present invention is a diagnostic which bolsters x-ray crystallography with the addition of semi-empirical quantum mechanics analysis

Methodology Applied
Scientific EffectQuantum mechanics:

Implementation Method 3

One particular study technique, neutron diffraction, can indeed correctly assess proteins in a sophisticated way

Methodology Applied
Scientific EffectNeutron diffraction: Neutron Diffraction

Data Source

PatentUS11688488B2Quantum mechanical/X-ray crystallography diagnostic for proteins
Publication Date: 2023.06.27 QUANTUMBIO INC
  • US11688488B2 patent drawing
  • US11688488B2 patent drawing
  • US11688488B2 patent drawing

AI summary

An analytic method for improving the efficiency in identifying protein molecular effect information using low resolution x-ray crystallography, by selecting and imaging a protein sample with low resolution x-ray crystallography and assaying the data thus generated as to local ligand strain energy value, followed by calculating a real-space difference density Z for each element and compiling ZDD data therefrom, followed by determining the true protomer/tautomer state of the protein sample by calculating Scorei according to the following equation so that the highest Scorei signifies the molecular effect information:Scorei={((ZDDi−μZDD)/σZDD)+((SEi−σSE)/σSE)}.