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Free keywords:
Adenosine Triphosphatases, Analysis, Cross-linking, Cross-Linking Reagents, Databases, Protein, DNA Helicases, Image Processing, Computer-Assisted, Integrative modeling, Mass spectrometry, Mass Spectrometry, Models, Molecular, Protein Conformation, Proteins, RNA Polymerase I, Saccharomyces cerevisiae Proteins, Software, Transcription Factors, Visualization, XL-MS
Abstract:
Structural characterization of large multi-subunit protein complexes often requires integrating various experimental techniques. Cross-linking mass spectrometry (XL-MS) identifies proximal protein residues and thus is increasingly used to map protein interactions and determine the relative orientation of subunits within the structure of protein complexes. To fully adapt XL-MS as a structure characterization technique, we developed Xlink Analyzer, a software tool for visualization and analysis of XL-MS data in the context of the three-dimensional structures. Xlink Analyzer enables automatic visualization of cross-links, identifies cross-links violating spatial restraints, calculates violation statistics, maps chemically modified surfaces, and allows interactive manipulations that facilitate analysis of XL-MS data and aid designing new experiments. We demonstrate these features by mapping interaction sites within RNA polymerase I and the Rvb1/2 complex. Xlink Analyzer is implemented as a plugin to UCSF Chimera, a standard structural biology software tool, and thus enables seamless integration of XL-MS data with, e.g. fitting of X-ray structures to EM maps. Xlink Analyzer is available for download at http://www.beck.embl.de/XlinkAnalyzer.html.
