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Photodissociative Cross-Linking of Non-covalent Peptide-Peptide Ion Complexes in the Gas Phase.
- Source :
-
Journal of the American Society for Mass Spectrometry . Aug2018, Vol. 29 Issue 8, p1706-1720. 15p. - Publication Year :
- 2018
-
Abstract
- We report a gas-phase UV photodissociation study investigating non-covalent interactions between neutral hydrophobic pentapeptides and peptide ions incorporating a diazirine-tagged photoleucine residue. Phenylalanine (Phe) and proline (Pro) were chosen as the conformation-affecting residues that were incorporated into a small library of neutral pentapeptides. Gas-phase ion-molecule complexes of these peptides with photo-labeled pentapeptides were subjected to photodissociation. Selective photocleavage of the diazirine ring at 355 nm formed short-lived carbene intermediates that underwent cross-linking by insertion into H-X bonds of the target peptide. The cross-link positions were established from collision-induced dissociation tandem mass spectra (CID-MS3) providing sequence information on the covalent adducts. Effects of the amino acid residue (Pro or Phe) and its position in the target peptide sequence were evaluated. For proline-containing peptides, interactions resulting in covalent cross-links in these complexes became more prominent as proline was moved towards the C-terminus of the target peptide sequence. The photocross-linking yields of phenylalanine-containing peptides depended on the position of both phenylalanine and photoleucine. Density functional theory calculations were used to assign structures of low-energy conformers of the (GLPMG + GLL*LK + H)+ complex. Born-Oppenheimer molecular dynamics trajectory calculations were used to capture the thermal motion in the complexes within 100 ps and determine close contacts between the incipient carbene and the H-X bonds in the target peptide. This provided atomic-level resolution of potential cross-links that aided spectra interpretation and was in agreement with experimental data.ᅟ<graphic></graphic> [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10440305
- Volume :
- 29
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- Journal of the American Society for Mass Spectrometry
- Publication Type :
- Academic Journal
- Accession number :
- 130749005
- Full Text :
- https://doi.org/10.1007/s13361-018-1980-4