Lloyd W. Sumner
Head, Biological Mass Spectrometry
Ph.D., Analytical Chemistry, 1993, Oklahoma State University, Stillwater, OK

My research interests include the development, advancement, and implementation of leading-edge instrumental techniques to broadly profile and identify the functional products of gene expression, namely proteins and metabolites. Profiling large numbers of proteins (Proteomics) and large numbers of metabolites (Metabolomics) simultaneously provides a broad "snap-shot" of the biochemical status of the cell. When these "snap-shots" are compared they provide a "movie" of the biochemical response of a cell and provide insight into the cellular response of an organism to external stimuli. Correlation of the expression profiles with genetic information also provides a unique way of understanding gene function and interrelationships between genes. The task of profiling large numbers of proteins and metabolites simultaneously is still quite challenging. We are approaching these challenges using mass spectrometry (MS) coupled with advanced separation technologies. Information obtained from these experiments is very specific and highly useful in chemical identification and characterization. Mass spectrometry is currently being used in conjunction with two-dimensional gel electrophoresis (2-DE), high performance liquid chromatography (HPLC/MS), and gas chromatography (GC/MS) to profile, compare and identify Medicago truncatula proteins and metabolites.

My research interests also seek to better understand the physical and chemical aspects of the many technologies being used in our laboratory. We want to use this understanding to improve and/or develop novel technologies. For example, we are interested in improving the efficiency of in-gel digestion and MALDI-TOFMS peptide mass mapping of low level proteins visualized in two-dimensional polyacrylamide gel electrophoresis (2-DE) with silver staining. Visualization by silver staining is achieved through the precipitation of silver metal that has been localized around the protein. This process results in the encapsulation the proteins and has long been viewed as an irreversible process; however, we have recently shown that silver can be chemically removed with hydrogen peroxide. Removal of the silver enhances the enzymatic digestion and MALDI-TOFMS peptide mass mapping efficiency. Our group is also interested in the energetics of the matrix-assisted laser desorption ionization (MALDI) event. MALDI is a means by which proteins, peptides and nucleotides are ionized prior to mass analysis. We want to understand how the optical spectroscopic and chemical properties of MALDI matrices affect ionization efficiency and the energetics of the MALDI experiment. Our goals included quantification of internal energies obtained during desorption and the systematic measurement of the absorbance, luminescence, and quantum yields of a large variety of MALDI matrices.

Personal Interests: As a long term resident of Oklahoma, I enjoy the rural environment and activities that accompany it. Personal hobbies include fishing, softball, volleyball, horses, casual gardening/farming, playing with my tractor, home improvements, and general tinkering. I also enjoy cooking and eating.