Centre de Recherches de Biochimie Macromoléculaire du CNRS, INSERM U 249, Route de Mende, BP 5051, 34033 Montpellier Cedex, France, Institute of Molecular Biology, Austrian Academy of Sciences, Billrothstrasse 11, A-5020, Salzburg, Austria, and Cold Spring Harbor Laboratory, P.O. Box 100, Cold Spring Harbor, New York 11724 (At 1996-01-01)
