title: Porphyrin triplet state as a potential spin label for nanometer distance measurements by PELDOR spectroscopy.
abstract: This work demonstrates, for the first time, the feasibility of applying pulsed electron-electron double resonance (PELDOR/DEER) to determine the interspin distance between a photoexcited porphyrin triplet state (S = 1) and a nitroxide spin label chemically incorporated into a small helical peptide. The PELDOR trace shows deep envelope modulation induced by electron-electron dipole interaction between the partners in the pair, providing an accurate distance measurement. This new labeling approach has a high potential for measuring nanometer distances in more complex biological systems due to the sensitivity acquired from the spin polarization of the photoexcited triplet state spectrum.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova , via Marzolo 1, 35131 Padova, Italy.
authors.forename: Marilena
authors.initials: M
authors.lastname: Di Valentin
authors.forename: Marco
authors.initials: M
authors.lastname: Albertini
authors.forename: Enrico
authors.initials: E
authors.lastname: Zurlo
authors.forename: Marina
authors.initials: M
authors.lastname: Gobbo
authors.forename: Donatella
authors.initials: D
authors.lastname: Carbonera