Mass spectrometry identifiable cross-linking strategy for studying protein-protein interactions

Anal Chem. 2005 Jan 1;77(1):311-8. doi: 10.1021/ac0488762.


A new mass spectrometry identifiable cross-linking strategy has been developed to study protein-protein interactions. The new cross-linker was designed to have two low-energy MS/MS-cleavable bonds in the spacer chain to provide three primary benefits: First, a reporter tag can be released from cross-link due to cleavage of the two labile bonds in the spacer chain. Second, a relatively simple MS/MS spectrum can be generated owing to favorable cleavage of labile bonds. And finally, the cross-linked peptide chains are dissociated from each other, and each then can be fragmented separately to get sequence information. Therefore, this novel type of cross-linker was named protein interaction reporter (PIR). To this end, two RINK groups were utilized to make our first-generation cross-linker using solid-phase peptide synthesis chemistry. The RINK group contains a bond more labile than peptide bonds during low-energy activation. The new cross-linker was applied to cross-link ribonuclease S (RNase S), a noncovalent complex of S-peptide and S-protein. The results demonstrated that the new cross-linker effectively reacted with RNase S to generate various types of cross-linked products. More importantly, the cross-linked peptides successfully released reporter ions during selective MS/MS conditions, and the dissociated peptide chains remained intact during MS(2), thus enabling MS(3) to be performed subsequently. In addition, dead-end, intra-, and inter-cross-linked peptides can be distinguished by analyzing MS/MS spectra.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Cross-Linking Reagents / chemical synthesis
  • Cross-Linking Reagents / chemistry*
  • Mass Spectrometry / methods*
  • Molecular Sequence Data
  • Protein Interaction Mapping / methods*
  • Ribonucleases / chemistry


  • Cross-Linking Reagents
  • Ribonucleases
  • ribonuclease S