drug-complex-system-builder

Build solvated, charge-neutralized OpenMM protein–ligand systems from PDB and SDF inputs.

144|21|Updated Jan 8, 2026
One-click install
npx skills add https://github.com/learningmatter-mit/AtomisticSkills --skill drug-complex-system-builder
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: drug-complex-system-builder
Source: https://github.com/learningmatter-mit/AtomisticSkills/tree/main/.agents/skills/drug-complex-system-builder
Command: npx skills add https://github.com/learningmatter-mit/AtomisticSkills --skill drug-complex-system-builder

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires openmm, openmmforcefields, openff-toolkit, rdkit, parmed, numpy, and includes scripts (resource) components.

What problem does it solve?

This Skill builds a complete, solvated, charge-neutralized protein–ligand complex suitable for OpenMM molecular dynamics from a prepared receptor structure and a validated ligand pose.

Core Features & Use Cases

  • OpenMM System Bundle Generation: Produces serialized OpenMM system.xml plus a full-precision state_initial.xml for exact restart.
  • Ligand + Protein Parameterization: Uses Amber ff14SB for the protein and OpenFF Sage (or GAFF with AM1-BCC charges) for ligand parameterization, then merges topologies.
  • Explicit Solvation and Ion Addition: Solvates with selectable water models and neutralizes/adds counterions to reach a target NaCl ionic strength, recording all provenance for reproducibility.
  • Use Case: When you already have a protonated receptor PDB and a docked/validated ligand SDF pose, use this to generate a simulation-ready box for running MD or downstream refinement workflows.

Quick Start

Use the drugmd-agent environment to run the build script with your receptor PDB, ligand SDF, chosen force fields, solvation settings, and an output directory.

Frequently Asked Questions about drug-complex-system-builder

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I build a solvated and ion-neutralized protein-ligand complex for OpenMM molecular dynamics?▼

To build a solvated protein-ligand complex for OpenMM molecular dynamics, you need a prepared receptor PDB and a validated ligand SDF. The system applies Amber ff14SB and OpenFF Sage force fields, solvates the structure, neutralizes charges, and outputs a ready-to-run system.xml.

What force fields are used for parameterizing ligands and proteins in OpenMM MD setup?▼

OpenMM MD setup uses Amber ff14SB for the protein and OpenFF Sage for ligand parameterization. Alternatively, GAFF with AM1-BCC charges can be applied to ensure accurate molecular dynamics simulation parameters.

Do I need to prepare receptor and ligand structures before generating an OpenMM system bundle?▼

Yes, you need a protonated receptor PDB and a docked ligand SDF pose before generating an OpenMM system bundle. Providing prepared structures allows the tool to correctly assign force fields, solvate the complex, and build the simulation box.

Can I control the water model and ionic strength when solvating a protein-ligand complex?▼

Yes, you can select your preferred water model and target NaCl ionic strength when solvating a protein-ligand complex. The process adds explicit solvent and counterions to neutralize charges, recording all provenance in a build_provenance.json file.

How does OpenMM handle ligand parameterization with OpenFF Toolkit?▼

OpenMM handles ligand parameterization with OpenFF Toolkit by applying AM1-BCC charges to the ligand SDF. This process generates the necessary parameters which are then merged with the protein topology to create a unified molecular dynamics system.

What simulation box shapes are supported for building solvated protein-ligand systems?▼

Building solvated protein-ligand systems supports simulation box construction for cube or common truncated shapes. This ensures the generated OpenMM molecular dynamics system fits standard periodic boundary conditions for accurate dynamics calculations.