Investigation of Peptide Fragmentation using Soft-Landing
EMSL Project ID
36392
Abstract
The goal of this research project is to better understand how peptides fragment at a molecular level. Much of the current knowledge on the structure of peptide fragment ions is based on indirect evidence, such as presumptive fragmentation mechanisms or fragmentation patterns in MSn experiments. In particular, the oxazolone and diketopiperazine pathways for b2+ ion formation have long been a subject of debate. In recent years a more direct method, IR action spectroscopy, enabled direct measurement of b2+ fragment ion structures (Ala-Ala, Ala-Gly, Tyr-Ile, and His-Ala) in the gas phase. Knowing the structures of the fragments will help to infer fragmentation mechanisms, and eventually the information might be used in future to improve protein identification algorithms.Although IR action spectroscopy is very powerful, it requires a free electron laser. There are only two free electron laser / mass spectrometry facilities in the world, so only a few days are allowed for a given research group per year. Another option for IR spectroscopy is "soft-landing" combined with reflective absorption IR spectroscopy (RAIRS). Soft-landing has been successfully used for structural studies of bio-molecules by many research groups. Dr. Julia Laskin has recently modified the PNNL soft-landing instrument by attaching an IR spectrometer directly to the vacuum chamber, which enables acquisition of cleaner IR spectra. In addition, the ion funnel device maximizes ion current at the surface and enables higher landing efficiency.
Sung Hwan Yoon is a graduate student from U. of Arizona. His goal is to use soft-landing to corroborate IR action spectroscopy results which indicate an oxazolone structure of Ala-Gly b2+ and a diketopiperazine structure of His-Ala b2+ and Val-Pro b2+. We believe the proposed experiments at PNNL will be of great value to our peptide fragmentation studies and will enable Sung Hwan to complete this portion of his dissertation research.
Project Details
Project type
Limited Scope
Start Date
2009-07-05
End Date
2009-09-04
Status
Closed
Released Data Link
Team
Principal Investigator