Energetics of Selective Cleavage at Acidic Residues Studied by Time-and Energy-Resolved Surface-Induced Dissociation in FT-ICR-MS
Surface-induced dissociation (SID) of four model peptides: LDIFSDF, LDIFSDFR, RLDIFSDF, and LEIFSEFR, was studied using a novel Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially equipped to perform SID experiments. The energetics and dynamics of selective cleavages at acidic residues were deduced by modeling the time- and energy-resolved fragmentation efficiency curves (TFECs) using an RRKM based approach developed in our laboratory. RRKM modeling revealed that addition of a basic residue to the C-terminus of a peptide has a very small effect on the dissociation threshold. However, the dynamics of dissociation is dramatically affected by the presence of the arginine. The Arrhenius pre-exponential factor for dissociation of LDIFSDF is two orders of magnitude higher than the pre-exponential factor for dissociation of arginine-containing peptides. The difference in the pre-exponential factors is indicative of a complex rearrangement process associated with selective fragmentation. Molecular mechanics modeling of the four parent ions gives some qualitative insight into the differences in fragmentation mechanisms.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US), Environmental Molecular Sciences Laboratory (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15002633
- Report Number(s):
- PNNL-SA-36326; 6291; TRN: US200412%%131
- Journal Information:
- International Journal of Mass Spectrometry, Vol. 222, Issue 1-3; Other Information: PBD: 1 Jan 2003
- Country of Publication:
- United States
- Language:
- English
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