Professor James P. Reilly of Indiana University is funded by the Chemistry Research Instrumentation and Facilities: Instrument Development (CRIF-ID) program to develop a tandem mass spectrometer for peptide sequencing and protein identification. Selectivity in peptide fragmentation is achieved through a non-thermal activation process which produces daughter ions that have more diverse structures than those formed by conventional approaches. A linear ion trap first stage accomplishes ion collection and selection. Cooled ions selected by the trap photodissociate upon exposure to vacuum ultraviolet laser light. High resolution and accurate mass analysis of the fragments is achieved in a reflectron time-of-flight (TOF) second stage. With this instrument the vacuum ultraviolet spectroscopy and photochemical propensities of peptide and protein ions are being investigated to improve the speed and accuracy of sequencing and analysis procedures.
Peptide sequencing and protein identification technology is of central importance to fields such as biochemistry and proteomics. Current methodologies identify a relatively small fraction of the mass spectra recorded in analyses of complex protein mixtures. They also encounter difficulties coping with mutations, post-translational modifications and genome sequencing errors. The ion trap-photofragmentation-TOF instrument under development is addressing these issues. Fundamental advances have the potential to impact our understanding of the molecular basis of disease and life processes.
