Interaction Energy Calculation for Drug Candidates

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Solution Overview

Problem

Current methods for calculating interaction energy between target molecules and drug candidates, especially in the presence of water molecules, face challenges with exponential calculation time and inefficiency in determining reliable relative relationships, as they either incur high computational complexity or reduce accuracy by approximating water molecules.

Innovation Solution

A method that extracts specific calculation-target water molecules influencing interaction energy between a target molecule and some drug candidate molecules, but not all, by performing first and second treatments in an interaction-calculation-target space, and only considers these molecules in the calculation, enhancing the reliability of relative interaction energy values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If quantum mechanics method is used to determine interaction energy, then measurement precision is improved, but calculation time exponentially increases

Engineering Contradiction:
Improveinteraction energy determination accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the water molecules into two categories: those that form hydrogen bonds with the protein-ligand complex (explicitly treated) and those that do not (approximated as continuum solvent). This segmentation allows the system to maintain high accuracy for critical interactions while reducing computational burden for less critical water molecules, thereby resolving the contradiction between precision and calculation time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different treatment qualities to different regions of water molecules based on their local interaction characteristics. Water molecules forming hydrogen bonds receive explicit quantum mechanical treatment for high precision, while bulk water molecules are approximated as a uniform continuum. This local differentiation maintains measurement precision where needed while reducing overall calculation time.

Inventive Principle:
Principle #3Local quality

2Loss of time

If water molecules are approximated with solvent as uniform continuum, then calculation time is reduced, but measurement precision deteriorates when hydrogen bonding occurs

Engineering Contradiction:
Improvecalculation timeVSAvoidinteraction energy determination accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent divides water molecules into two distinct groups based on their hydrogen bonding status. Those that form hydrogen bonds with the complex are extracted and treated explicitly, while others are approximated as continuum solvent. This segmentation preserves measurement precision for hydrogen-bonding water molecules while maintaining computational efficiency for the majority of bulk water molecules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies enhanced treatment quality specifically to water molecules in the hydrogen-bonding region, while using standard continuum approximation for bulk water regions. This local quality enhancement ensures that measurement precision is maintained where it matters most (at the protein-ligand interface) while keeping overall calculation time reduced.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If all water molecules are expressly considered, then measurement precision is improved, but calculation time exponentially increases

Engineering Contradiction:
Improverelative interaction energy reliabilityVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential water molecules (those forming hydrogen bonds) from the complete set of water molecules for explicit treatment. This extraction approach maintains measurement precision for the critical subset of water molecules that influence relative interaction energy, while avoiding the exponential calculation time increase that would result from treating all water molecules explicitly.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach efficiently calculates interaction energy with high reliability by selectively considering only the influential water molecules, reducing computational complexity and maintaining accuracy, thereby improving the efficiency and reliability of interaction energy calculations.

Implementation Method 1

the continuum approximation is destroyed when a complex of the protein and the ligand is bonded to water with hydrogen bonds

Methodology Applied
Scientific EffectHydrogen bonding:

Data Source

PatentEP3239874B1Interaction energy calculation method, calculation device, and program
Publication Date: 2021.04.07 FUJITSU LTD
  • EP3239874B1 patent drawingFigure 1~3
  • EP3239874B1 patent drawingFigure 4~5
  • EP3239874B1 patent drawingFigure 6A~6B

AI summary

A method, which includes: extracting one or more calculation-target water molecules that influence at least interaction energy between the target molecule and some of the drug candidate molecules, but not the interaction energy between the target molecule and all of the drug candidate molecules; and calculating each interaction energy between the target molecule and each of the drug candidate molecules with only considering the one or more calculation-target water molecules as water molecules treated positively in a calculation of each interaction energy, and with considering the one or more calculation-target water molecules only in a calculation of interaction energy which the one or more calculation-target water molecules influence, wherein the method is a method for calculating interaction energy between the target molecule and the drug candidate molecules using a calculator.