title: The Electronic State of Flavoproteins: Investigations with Proton Electron-Nuclear Double Resonance.
abstract: Electron-nuclear double resonance (ENDOR) spectroscopy provides useful information on hyperfine interactions between nuclear magnetic moments and the magnetic moment of an unpaired electron spin. Because the hyperfine coupling constant reacts quite sensitively to polarity changes in the direct vicinity of the nucleus under consideration, ENDOR spectroscopy can be favorably used for the detection of subtle protein-cofactor interactions. A number of pulsed ENDOR studies on flavoproteins have been published during the past few years; most of them were designed to characterize the flavin cofactor by means of its protonation state, or to detect individual protein-cofactor interactions. The aim of this study is to compare the pulsed ENDOR spectra from different flavoproteins in terms of variations of characteristic proton hyperfine values. The general concept is to observe limits of possible influences on the cofactor's electronic state by surrounding amino acids. Furthermore, we compare ENDOR data obtained from in vivo experiments with in vitro data to emphasize the potential of the method for gaining molecular information in complex media.
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr.21, 79104 Freiburg, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Schleicher
authors.affiliation: Institut für Experimentalphysik, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors.forename: Ringo
authors.initials: R
authors.lastname: Wenzel
authors.affiliation: CNRS, University of Paris VI, Paris, France.
authors.forename: Margret
authors.initials: M
authors.lastname: Ahmad
authors.affiliation: Fachbereich Biologie, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Alfred
authors.initials: A
authors.lastname: Batschauer
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany.
authors.forename: Lars-Oliver
authors.initials: LO
authors.lastname: Essen
authors.affiliation: Department of Molecular Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hitomi
authors.affiliation: Department of Molecular Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA.
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Getzoff
authors.affiliation: Institut für Experimentalphysik, Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Bittl
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr.21, 79104 Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Weber
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr.21, 79104 Freiburg, Germany.
authors.forename: Asako
authors.initials: A
authors.lastname: Okafuji