I’ve mentioned Silicos-it in the past and I thought I’d highlight them again since they have had a major makeover, the website has moved and the tools have been updated and renamed.

Silicos-it has contributed it’s expertise to the chemoinformatics community by porting its source code into the open source domain. Examples include the spectrophore descriptors, the filtering program filter-it and the pharmacophore tool align-it.

Command-line tools

Filter-it™ is a command-line program for filtering molecules with unwanted properties out of a set of molecules. The program comes with a number of pre-programmed molecular properties that can be used for filtering.

I used the filter-it (previously called Sieve) in a Vortex script, I’ve rewritten the script and the tutorial to account for the name change.

Strip-it™ is a tool to extract molecular scaffolds according predefined rules. These rules are based on the definitions of scaffolds as described by Bemis & Murcko (J. Med. Chem. 1996, 39, 2887), Pollock (J. Chem. Inf. Model. 2008, 48, 1304) and Schuffenhauer (J. Chem. Inf. Model. 2007, 47, 47).

Align-it™ is a pharmacophore-based tool to align small molecules. The tool is based on the concept of modeling pharmacophoric features by Gaussian 3D volumes instead of the more common point or sphere representations. The smooth nature of these continuous functions has a beneficent effect on the optimisation problem introduced during alignment.

Shape-it™ is a shape-based alignment tool by representing molecules as a set of atomic Gaussians. The software is based on the method described by Grant and Pickup (J. Phys. Chem. 1995, 99, 3503).

Spectrophores are one-dimensional descriptors generated from the property fields surrounding the molecules. This technology allows the accurate description of molecules in terms of their surface properties or fields. Comparison of molecules’ property fields provides a robust structure-independent method of aligning actives from different chemical classes. When applied to molecules such as ligands and drugs, Spectrophores can be used as powerful molecular descriptors in the fields of chemoinformatics, virtual screening, and QSAR modeling. The Spectrophore code was developed by Silicos, and donated to the OpenBabel project in July 2010.