EPR Spectra of Transition-Metal Proteins: the Benefits of Data Deposition in Standard Formats

Abstract

Electron paramagnetic resonance (EPR) spectroscopy can provide answers to significant questions about structure and function in biochemistry. Often EPR spectra of proteins containing transition-metal centers and radicals show the influence of electron spin–spin interactions between paramagnets. Analysis of these spectra provides information about distances and molecular orientations. For small proteins, the shape of the EPR spectra is sensitive to freezing effects, and to changes in the solvent environment; intermolecular spin–spin interactions are also observed. For large complex proteins, details of the EPR spectra are often highly conserved in evolution. Reference spectra of paramagnetic proteins are an aid to identification. The sharing of data is becoming a requirement in the public funding of research, and deposition in public databases is already standard for information such as protein structures and gene sequences. This would require the adoption of standard file formats, such as JCAMP-DX (Joint Committee on Atomic and Molecular Physical Data Exchange) or Bruker BES3T (Bruker EPR Standard for Spectrum Storage and Transfer). An archive of EPR spectra of different types of paramagnetic proteins would assist the identification of paramagnetic centers in biological materials. It would increase the profile of research data, allow comparison of different studies, and further interpretation of data in the light of subsequent discoveries.