Research Advisor: Dr. Paul DeYoung
An Ion Beam Analysis (IBA) technique of simultaneous Particle-Induced X-ray Emission (PIXE) and Nuclear Reaction Analysis (NRA) is being developed to determine the complete stoichiometry of metalloproteins. Even though approximately one third of all proteins are metalloproteins, the stoichiometric ratios of the metalloproteins are still largely unknown. Current elemental analysis procedures are capable of characterizing which metals are in a protein, but it is difficult to determine the absolute quantity of metal atoms per protein. To address this, an IBA method is being developed which incorporates coupled PIXE and NRA. PIXE characterizes the areal density of the metal elements in the sample, while NRA uses Rutherford scattering cross-sections to determine the areal density of the proteins. This combination allows for an accurate determination of the desired metal-to-protein ratio. The method is being validated with the Cyanocobalamin (B12) and Cytochrome C Equine proteins which have known metal-to-protein stoichiometries. After the method has been validated, the IBA technique will be extended to new metalloproteins. This methodology will allow for future characterization of metalloproteins with unknown stoichiometry.
This work is supported by the National Science Foundation under grant 1306074.