Hope College Physics Department
Research Experiences for Undergraduates
Summer 2010
Project Summary


Project Title: Ion Beam Analysis of Metalloprotein Stoichiometry
Student Name: Andrew Mc Cubbin
Student's Home Institution: Hope College
Research Advisor: Dr. Paul DeYoung and Dr. Graham Peaslee
Source of Support:

This material is based upon work supported by the Howard Hughes Medical Institute and by the National Science Foundation under NSF-PHY Grant No. 0969058.

Particle induced X-ray emission (PIXE) spectroscopy is a non-destructive ion beam analysis technique well suited to determine the concentrations of heavy elements. Particle elastic scattering analysis (PESA) is a similar technique which measures the areal density of a thin target by quantifying the energy loss of the transmitted ions. A combination of PESA and PIXE has been developed to provide a quantitative technique for the determination of stoichiometric metal ion ratios in metalloproteins. About a third of all proteins are metalloproteins, and most do not have known stoichiometric compositions for the metals they contain. Current work focuses on establishing a standard method in which to prepare protein samples. Two methods of preparation are currently being investigated. The first involves spotting protein solutions on aluminized polyethylene terephthalate and allowing them to dry. The second uses the process of native polyacrylamide gel electrophoresis in order to separate proteins and then drying them to provide adequately thin samples. These methods are compared for several proteins to determine their respective effectiveness and to develop a standard model for running ion beam analysis of metalloproteins

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