1. Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Strasse des 17, Juni 135, D-10623 Berlin, Germany, Dipartimento di Chimica Fisica Universita di Padova, Via Loredan 2, 35131 Padova, Italy, and Department of Plant Biology and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287