Investigation of Unknown Proteins

In collaboration with scientists at Structural Proteomics at the University of Toronto we use EPR to study unknown proteins that are isolated and purified at Toronto and try to determine the nature of the proteins and which class they belong to. Currently, we are trying to determine the properties of a protein with a bright purple color (nicknamed “deep purple”). Preliminary X-band EPR experiments indicate that it might belong to a class of proteins called “purple acid phosphatases”. Our spectra indicate the presence of Fe ions at sites where they experience different rhombicities of the crystal field. We are planning a number of experiments, including pH titrations and small molecule substrate binding, and more detailed simulations to determine how many Fe ions we have at the active site. If the Fe ions are coupled, we will also determine the nature and the strength of the interactions.

X-band EPR spectra of "deep purple"

Matt Giordanengo carrying out experiments on "deep purple"