# Using PDB2PQR¶

Note

Before you begin! PDB2PQR funding is dependent on your help for continued development and support. Please register before using the software so we can accurately report the number of users to our funding agencies.

PDB2PQR is often used together with the APBS software; e.g., ,in the following type of workflow

1. Start with a PDB ID or locally generated PDB file (see PDB molecular structure format).
2. Assign titration states and parameters with pdb2pqr to convert the biomolecule and ligands to PQR format (see PQR molecular structure format).
3. Perform electrostatics calculations with apbs (can be done from within the PDB2PQR web server).
4. Visualize results from within PDB2PQR web server or with Other software.

## Web server use¶

Most users will use PDB2PQR through the web server (after registering, of course). However, it is also possible to install local versions of PDB2PQR and run these through the command line.

## Command line use¶

pdb2pqr30 [options] --ff={forcefield} {path} {output-path}


This module takes a PDB file as input and performs optimizations before yielding a new PQR-style file in {output-path}. If {path} is a PDB ID it will automatically be retrieved from the online PDB archive.

In addition to the required {path} and {output-path} arguments, pdb2pqr30 requires one of the following options:

• --ff=FIELD_NAME specifying the forcefield to use. Run pdb2pqr30 --help to see specific options.
• --userff=USER_FIELD_FILE specifying a user-created forcefield file. Requires --usernames and overrides --ff.
• --clean specifying no optimization, atom addition, or parameter assignment, just return the original PDB file in aligned format. Overrides --ff and --userff options.

pdb2pqr30 --help


The following tools are also provided with PDB2PQR. They all accept the --help option which provides information about usage of these tools.

#### dx2cube¶

Converts an OpenDX volumetric (e.g., as generated by APBS) to a Gaussian cube-format file.

#### inputgen¶

Generates an APBS input file with recommended settings.

#### psize¶

Provides size information about the molecular system and suggests APBS settings.