1School of Crystallography and Institute of Structural Molecular Biology, Birkbeck, University of London, Malet Street, London, WC1E 7HX United Kingdom
2Department of Biochemistry and Molecular Biology, University College London, Gower Street, London, WC1E 6BT United Kingdom
3Centre de Biochimie Structurale, CNRS UMR5048; INSERM, U554, University of Montpellier I, 29, rue de Navacelles, 34094 Montpellier, France
4Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, 256 Gray’s Inn Road, London, WC1X 8LD United Kingdom