Electron paramagnetic resonance in structural studies of proteins, peptides, biomembranes, polymers, model molecules and their complexes with transition metals

Abstract

Continuous-Wave (CW) Electron Paramagnetic Resonance (EPR) has been widely used in structural studies of a variety of problems, inc1uding many interesting biologically relevant systems. It has contributed very significant1y to the characterization of metal binding sites in proteins, to the study of the dynamic structure of biomembranes and to the kinetics of several processes such as electron transfer. More recent1y, EPR has been experiencing a resurgence especially due to the introduction of new CW methodologies, such as site-directed spin labeling, as well as to its extension to very high frequencies and to the appearance of modem time resolved techniques (pulsed techniques). The latter has taken advantage of the incredible instrumental development achieved during the last few years, thus taking EPR to a new level, where pulsed spectrometers are commercially available. However, unlike NMR, which has almost abolished the continuous wave methods, EPR still makes use of these experiments in a great number of situations. Some very important results have been obtained in systems like metalloproteins and polymers. This project is mainly focused on the applications of EPR to structural studies of proteins, biomembranes, small peptides, model molecules and their complexes with transition metal ions. The establishment of an Electron Paramagnetic Resonance Center congregates several research projects traditionally under investigation in the Molecular Biophysics Group (IFSCIUSP). The use of EPR in its various forms (multifrequencies, CW-EPR, pulsed EPR) is the common point amongst the different projects. The general interests are of physical, chemical and biological relevance. More specifically, the research projects can be divided in three main areas: 1. Biological membranes - involving the projects: Dihydroorotato dehydrogenase from Xylella fastidiosa and its interactions with membranes, Dynamic structure of biologically relevant membranes and peptide-lipid interactions, Permeation process across the capsule of the microalga by EPR technique, and Development of a S-band EPR spectrometer. 2. Metalloproteins and their model systems: involving the projects , Comparative studies of hemeproteins and iron-containing proteins under the influence of conformational modulators, Strucutural studies of non-heme metaloproteins, Transitions ion complexes with small biologically relevant ligands (Cu, Mn, Vo, etc, aminoacids, dipeptides, etc...), and Redox processes and the reaction mechanisms of model porfirins...(AU)