Cross-link guided molecular modeling with ROSETTA

PLoS One. 2013 Sep 17;8(9):e73411. doi: 10.1371/journal.pone.0073411. eCollection 2013.

Abstract

Chemical cross-links identified by mass spectrometry generate distance restraints that reveal low-resolution structural information on proteins and protein complexes. The technology to reliably generate such data has become mature and robust enough to shift the focus to the question of how these distance restraints can be best integrated into molecular modeling calculations. Here, we introduce three workflows for incorporating distance restraints generated by chemical cross-linking and mass spectrometry into ROSETTA protocols for comparative and de novo modeling and protein-protein docking. We demonstrate that the cross-link validation and visualization software Xwalk facilitates successful cross-link data integration. Besides the protocols we introduce XLdb, a database of chemical cross-links from 14 different publications with 506 intra-protein and 62 inter-protein cross-links, where each cross-link can be mapped on an experimental structure from the Protein Data Bank. Finally, we demonstrate on a protein-protein docking reference data set the impact of virtual cross-links on protein docking calculations and show that an inter-protein cross-link can reduce on average the RMSD of a docking prediction by 5.0 Å. The methods and results presented here provide guidelines for the effective integration of chemical cross-link data in molecular modeling calculations and should advance the structural analysis of particularly large and transient protein complexes via hybrid structural biology methods.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Mass Spectrometry
  • Protein Structure, Secondary
  • Proteins / chemistry*
  • Software*

Substances

  • Proteins

Associated data

  • PDB/1U6R

Grants and funding

This project was funded in part by ETH Zurich, the Commission of the European Communities through the PROSPETS consortium (EU FP7 projects 201648, 233226) and by SystemsX.ch – The Swiss Initiative for Systems Biology. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.