1. Department of Biochemistry and Molecular Biology and Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria 3800, Australia, Department of Microbiology, Faculty of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, and Inserm, Unite 428, Universite Paris V, 75270 Paris Cedex 06, France