BioGem Blog

Homology or comparative protein structure modeling is a complex process, but with the help of tools like Modeller , it becomes more accessible and efficient. It's fascinating how the program can automatically calculate a model with all non-hydrogen atoms based on an alignment of a sequence to be modeled with known related structures. The input to Modeller are restraints on the spatial structure of the amino acid sequence(s) and ligands to be modeled, and the output is a 3D structure that satisfies these restraints as well as possible. It's amazing how the program can derive restraints from various sources such as related protein structures, NMR experiments, rules of secondary structure packing, cross-linking experiments, fluorescence spectroscopy, image reconstruction in electron microscopy, site-directed mutagenesis, residue-residue and atom-atom potentials of mean force, and even intuition. The program can operate on various spatial features defined by atoms or pseudo at...

AutoDock is a free molecular modeling simulation suite mainly used for molecular docking. It consists of two programs, namely AutoGrid and AutoDock. The three variants of AutoDock are AutoDock 4.2.6 , AutoDock Vina 1.2.3 (a successor of AutoDock), and AutoDock GPU . AutoDock or Vina use PDBQT (Protein Data Bank (PDB), Partial Charge (Q), and Atom Type (T)) molecular structure file format for input and output. But, most molecular analysis and visualization tools accept the PDB file format. The video tutorial for converting AutoDock or Vina results in a complex PDBQT file format to PDB file format is below.

Chimera (or UCSF Chimera ) is an interactive molecular visualization and analysis program developed by the Resource for Biocomputing, Visualization, and Informatics ( RBVI ) at the University of California, San Francisco ( UCSF ). ChimeraX (or UCSF ChimeraX ) is the next-generation molecular visualization program, which is a successor of Chimera. The Chimera/ChimeraX program supports analyzing various molecular structures and related data, including sequence alignments, docking results, molecular assemblies, electron density maps, trajectories, and conformational ensembles. It can be downloaded freely for academic, government, nonprofit, and personal use. Protein-Ligand Interaction Models In the protein-ligand interaction model, proteins or ligands are represented by a wire-frame model / stick model / ball-and-stick model / cartoon model / space-fill model / surface model, but not both. The interactions between protein and ligand atoms is represented by dotted or dashed lines. T...

The three-dimensional (3D) structure of a compound can be retrieved using standard chemical nomenclature from the most popular databases, namely PubChem , ChEBI , ChEMBL , ChemSpider , CSD , ZINC , DrugBank , etc. If the 3D structure or chemical data is not available in the database, this simple tutorial helps you to predict the most optimal structure. The tools used in this tutorial are OPSIN (Open Parser for Systematic IUPAC Nomenclature), CACTUS , and Chimera .