Hope College Physics Department Research Experiences for Undergraduates Summer 2012 Project Summary

Particle-Induced X-ray Emission Spectroscopy (PIXE) and Nuclear Reaction Analysis (NRA) are two highly sensitive ion beam analytical techniques which probe the elemental constitution and areal density, respectively, of a sample. Using a 1.7 MV tandem electrostatic particle accelerator, these methods have been utilized simultaneously to determine the identity and stoichiometry of metal atoms within protein samples of known metal content; results indicate the technique is a useful analytical tool which can be accurately extended to proteins of hitherto unknown metal stoichiometries. The nondestructive technique, originally developed for dried protein spots on a suitably thin support, has been extended for metalloproteins suspended in polyacrylamide gel. This allows use of the technique in biochemical applications in which proteins are separated by polyacrylamide gel electrophoresis (PAGE), after which proteins are not easily removed from the gel. Various methods of sample preparation such as sample mounting and gel drying have been considered. Additionally, such factors as the thickness, constitution, and possible contaminants of the gel have been investigated and are reported.

Publications and Presentations:
“Ion Beam Analysis of Metalloprotein Stoichiometry”, Andrew McCubbin. 2011 Celebration of Undergraduate Research, Hope College, April 15, 2011.

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