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CX, an algorithm that identifies protruding atoms in proteins.

Alessandro Pintar·Oliviero Carugo·Sándor Pongor
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Abstract

MOTIVATION: A simple and fast algorithm is described that calculates a measure of protrusion (cx) for atoms in protein structures, directly useable with the common molecular graphics programs. RESULTS: A sphere of predetermined radius is centered around each non-hydrogen atom, and the volume occupied by the protein and the free volume within the sphere (internal and external volumes, respectively) are calculated. Atoms in protruding regions have a high ratio (cx) between the external and the internal volume. The program reads a PDB file, and writes the output in the same format, with cx values in the B factor field. Output structure files can be directly displayed with standard molecular graphics programs like RASMOL, MOLMOL, Swiss-PDB Viewer and colored according to cx values. We show the potential use of this program in the analysis of two protein-protein complexes and in the prediction of limited proteolysis sites in native proteins. AVAILABILITY: The algorithm is implemented in a standalone program written in C and its source is freely available at ftp.icgeb.trieste.it/pub/CX or on request from the authors.

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AlgorithmsComputer GraphicsDatabases, ProteinModels, ChemicalModels, MolecularMolecular StructureProgramming LanguagesProtein ConformationProtein Interaction MappingProteinsSensitivity and SpecificitySerpinsSoftwareTrypsinComparative StudyJournal Article

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Alessandro Pintar, Oliviero Carugo, Sándor Pongor. 2002. CX, an algorithm that identifies protruding atoms in proteins.. https://doi.org/10.1093/bioinformatics%2F18.7.980

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