Quantitative Analysis of a Metalloprotein Compositional Stoichiometry with PIXE and PESA
An absolute measurement of the heavy element concentrations in a dried sample of aqueous protein solution has been combined with the absolute measurement of protein molecular concentration in the same sample. The ratio of these two measurements yields the metal-to-protein compositional stoichiometry of the metalloprotein. This combination of two Ion Beam Analysis techniques (Particle-Induced X-ray Emission and Proton Elastic Scattering Analysis) allows quantitative assessment of the metal atom to protein ratio in metalloproteins without direct measurement of sulfur atoms within the protein for the first time. While these results only demonstrate success with a single well-known metalloprotein, this combination of measurement ratios holds promise for future Ion Beam Analysis studies of metalloproteins.
Published in: Nuclear Instruments & Methods inPhysics Research Section B-Beam, Interactions with Materials and Atoms, Volume 268, Issue 10, May 15, 2010, pages 1671-1675. Copyright © 2010 Elsevier Science BV, Amsterdam. The final published version is available at: http://dx.doi.org/10.1016/j.nimb.2010.02.128