1. Service de Biophysique, Dept, de Biologie, CEA /INRA Saclay, 91191 Gif sur Yvette, France
2. The University of Chicago, Dept, of Molecular Genetics and Cell Biology, 920 East 58th Street, Chicago, Illinois 60637, U.S.A.
3. UPR 407, Photosynthèse, C NRS, 91198 Gif sur Yvette, France