The Department of Chemistry and Environmental Health Sciences Center (EHSC) at Oregon State University requests funds from the NCRR to purchase a new Q-T of Hybrid Quadrupole/Orthogonal Time- of-Flight Mass Spectrometer and Data System (MS/MS/DS). This instrument is needed to fill a void in the existing capabilities at OSU to solve ongoing problems in the mass spectrometry laboratory. The instrumentation that is currently available in the OSU mass spectrometry laboratory does not have the combined sensitivity and resolving power necessary to solve many of the protein structural problems we are increasingly encountering. The research projects that will be supported by the new instrument fall generally into two major areas. These are 1) protein identification from analysis of 2-D gel spot digests and 2) hydrogen/deuterium exchange studies on folding intermediates and conformational states resulting from modifications and ligand interactions. In addition the instrument will be used for identifying sites of protein modifications and phosphorylation, peptide sequences, and marine alkaloid structures. The major users have NIH funding to carry out the studies described in the application. Although EHSC, departmental funds and facility charges have provided support for the mass spectrometry facility, there is no mechanism in place to raise sufficient funds to purchase major equipment. A secondary role of the new instrument will be to provide campus-wide mass spectrometry support for those investigators requiring high resolution, mass accuracy, and sensitivity. The OSU Mass Spectrometry Facility also supports the mass spectrometry needs of the other major Oregon academic institutions.