1. Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
2. York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, UK
3. INRA and AgroParisTech, Microbiologie et Génétique Moléculaire, F-78850 Thiverval-Grignon, France
4. Department of Medical Microbiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
5. School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia