Structural and functional studies on type III and type VI secretion system proteins

Abstract

Secretion systems in pathogenic bacteria play a major role in delivering virulence proteins into host cells. To date, six types of secretion systems have been identified in gram-negative pathogenic bacteria. The crystal structure and function of GrlR, a type III secretion system (T3SS) protein from Enterohemorrhagic Escherichia coli (EHEC) is reported in chapter 2. In chapter 3 we report the structure of lipid-GrlR complex and the details of the lipid binding of GrlR. In chapter 4 we report the crystal structure and oligomerisation studies of EvpC, a type VI secretion system protein from Edwardsiella tarda. Proteins associated with a secretion system are new targets for potential drugs and vaccines, which can prevent diseases by impairing essential virulence properties. Our studies broaden the understanding of the structure, function and assembly of protein secretion system, particularly the type III and VI secretion systems in gram-negative bacteria that will ultimately aid in drug development.