Tools
How to build molecules in Pymol?

Pymol [1] has many functions that you keep finding on exploration. In this article, we will explain how to draw molecules in Pymol.
Assuming you have Pymol installed on your system. If not, then read this article to install Pymol on Ubuntu.
Getting Started
- Open Pymol on Ubuntu either by typing
pymol
on the terminal and on Windows by double-clicking the app. - Go to the top-right corner where you can see some options such as Reset, Zoom, Draw, etc. In the last row, you will see an option namely, Builder. Click on it.
- After clicking on it, you will see a small window consisting of some chemical structures, atoms, and bonds.
Building simple molecule
- Choose whatever chemical structure you want, for example, benzene, carbon, oxygen, and so on.
- Click on a structure, for instance, benzene.
- Go to the right-hand side panel. You will see three tabs: (i) Create As a New Object, (ii) Combine w/ Existing Object, and (iii) Done.
- Click on the first tab, i.e.,
Create As a New Object
. - Now click on the blank space on the Pymol screen. You will see a benzene structure.
- Now add other atoms or bonds as per your requirement.
- You can undo any step by pressing Ctrl+Z, create bonds, clear up the whole screen, add charge, set up a cycle bond (for that click on
Cycle
written in front of ‘Bonds:’ in the builder window) and so on.
Similarly, you can add some amino acids to the structure.
- Repeat the above steps and then switch to the ‘Protein’ tab on the Builder window.
- Click on the amino acids you wish to add to the structure.
- After finishing the structure, you can save it as a PDB file.
Saving the molecule in PDB format
- Go to
File --> Export Molecule --> PDB Options --> Write CONECT records for all bonds --> Save.
- You can select other formats such as MOL2, Maestro, XYZ, and so on.
References
- The PyMOL Molecular Graphics System, Version 1.2r3pre, Schrödinger, LLC.
Software
DS Visualizer: Uses & Applications

Discovery Studio (DS) Visualizer (from BIOVIA) is a visualization tool for viewing, sharing, and analyzing proteins [1]. Here are some uses and applications of DS Visualizer.
Software
Protein structure & folding information exploited from remote homologs.

Remote homologs are similar protein structures that share similar functions, but there is no easily detectable sequence similarity in them. A new study has revealed that the protein folding information can be exploited from remote homologous structures. A new tool is developed to recognize such proteins and predict their structure and folding pathway. (more…)
RNA-seq analysis
Pathonoia- A new tool to detect pathogens in RNA-seq data.

Detecting viruses and bacteria in RNA-seq data with less false positive rate is a difficult task. A new tool is introduced to detect pathogens in RNA-seq data with high precision and recall known as Pathonoia [1].
Software
AlphaFill- New algorithm to fill ligands in AlphaFold models.

AlphaFold is a popular artificial intelligence based protein prediction tool [1]. Though it predicts good protein structures, it lacks the capability to predict the small molecules present in the structure such as ligands. For this purpose, AlphaFill is introduced by Hekkelman et al.,[2]. (more…)
Software
How to calculate binding pocket volume using PyVol plugin in PyMol?
Software
How to generate electron density map using Pymol?

Electron density maps are available for most of the protein structures in PDB. Therefore, in this article, we are using PDB to generate electron density maps in Pymol.
Software
Installing PyVOL plugin in Pymol on Ubuntu (Linux).

PyVOL [1] is an excellent plugin of Pymol [2] for pocket visualization of proteins. In this article, we will install the PyVOL plugin in Pymol on Ubuntu. (more…)
Tips & Tricks
How to download FASTA sequences from PDB for multiple structures?

In this article, we are going to download FASTA sequences for multiple structures from PDB [1]. We need to have PDB IDs only for input. (more…)
Software
How to install Kpax on Ubuntu (Linux)?

Kpax is a bioinformatics program to search and align protein structures [1]. It is currently available for Linux platforms only. In this article, we are going to install the latest version of Kpax (5.1.3) on Ubuntu (Linux). (more…)
Secondary structure
How to run do_dssp command (mkdssp) in Gromacs 2022?

In the latest version of GROMACS (2022) [1], there are some issues regarding the gmx do_dssp command. Apparently, this command either does not run displaying a fatal error, or if it runs then it does not read any frame from MD simulation files. In this article, we are going to run the same command for GROMACS 2022. (more…)
Software
Installing SMINA on Ubuntu (Linux).

SMINA is a fork of AutoDock Vina supporting better scoring function and high-performance energy minimization [1]. In this article, we are going to install SMINA on Ubuntu (Linux). (more…)
Software
How to install ClusCo on Ubuntu (Linux)?

ClusCo is a bioinformatics software to perform clustering and comparison of protein models [1]. In this article, we are going to install ClusCo on Ubuntu (Linux). (more…)
Software
How to run LigAlign plugin on Pymol?

Running a plugin on an old version of Pymol [1] can give you multiple errors that are not easy to troubleshoot. For example, LigAlign plugin [2] runs on an old version of Pymol. Previously, we explained how to install LigAlign on Pymol. In this article, we will run the LigAlign command on Pymol. (more…)
Software
How to install the LigAlign plugin on Pymol on Ubuntu (Linux)?

Few errors appear when we try to run the LigAlign plugin [1] in Pymol [2]. For example, if you try to run the ligand_alignment plugin, it will give you multiple errors including “Unable to initialize LigAlign v1.00“, or “can’t run LigAlign v1.00” or “incorrect Python syntax” or “Plugin has been installed but initialization failed“. In this article, we explain the reason for this issue and how you can rectify these errors. (more…)
Software
How to install multiple Pymol versions on Ubuntu (Linux)?

Sometimes we need to access old versions of Pymol [1]. Running some plugins on Pymol is difficult due to Python incompatibility. New Pymol versions require Python 3.x whereas older versions run on Python 2.x. Therefore, we need to maintain multiple versions of Pymol on a single system. In this article, we will install Pymol 1.7.x along with the latest version (Pymol 2.5.2) on Ubuntu. Later, we will create shortcuts for them.
Software
[Tutorial] Installing Pymol on Mac OS.

Previously, we provided a tutorial for Pymol installation on Ubuntu. In this article, we are going to install Pymol on Mac OS. (more…)
Software
How to install VMD on Ubuntu?

In this article, we are going to install VMD [1] on Ubuntu. (more…)
MD Simulation
How to install GROMACS on Apple M1 (MacOS)?

We have provided a few articles on GROMACS installation on Ubuntu. In this article, we are going to install GROMACS [1] on Mac OS. (more…)
Software
PyMol: Uses & Applications

PyMol is one of the most widely used bioinformatics software. Generally, it is used as a molecular viewer to visualize macromolecules and small molecules. In this article, we are discussing several uses and applications of PyMol. (more…)
MD Simulation
How to take snapshots of structure at specific times in GROMACS?

It is important to see the behavior of protein during an MD simulation. This can be achieved by taking snapshots in the form of PDB format. In this article, we have provided a few commands that you can use to take snapshots of a complete system or protein during MD simulation. (more…)
You must be logged in to post a comment Login