Electron spin echo envelope modulation (ESEEM) spectroscopy as a tool to investigate the coordination environment of metal centers

The applications of electron spin echo envelope modulation (ESEEM) spectros copy to study paramagnetic metal centers in metalloproteins and bioinorgani c complexes are reviewed, with special attention to the novel spectroscopic techniques applied and the structural information obtained. We summarize t he physical principles and experimental techniques of ESEEM, the spectral s hapes and the methods for their analysis. The physical meaning of the spin Hamiltonian parameters is highlighted in conjunction with their utilization for obtaining structural information. (C) 2000 Elsevier Science S.A. All r ights reserved.