Abstract: Type three secretion systems are crucial for virulence of many human pathogenic bacteria either in their role as bacterial flagellar or as toxin injection systems. Despite many decades of study our understanding of the core complexes required for function in these nano-machines had largely stalled. Recent advances in single particle cryo-em methodologies now allow us to build de novo atomic models for many of the complexes involved in type three secretion systems that have been recalcitrant to crystallisation over the years. Structures of these complexes are revealing major holes in our understanding from mis-assigned symmetries to supposed membrane proteins that adopt out of membrane-locations within the intact assemblies requiring re-analysis of earlier functional work in the context of the architecture revealed. New structures will be presented and their implications for function discussed.

Biography: Susan holds the Chair of Microbiology in the Sir William Dunn School of Pathology at the University of Oxford. She is primarily interested in what structural biology can help us understand about the way in which pathogens and their hosts first encounter each other. At times this work has led to potential therapeutic opportunities with structures suggesting opportunities for novel vaccination strategies, but the primary focus is using structure to inform functional studies to elucidate basic biological processes.