Crystallographic mapping of the serpinopathies. (360G-Wellcome-078211_Z_05_Z)

Serpins (predominantly serine proteinase inhibitors) control critical proteolytic cascades in animals, plants, prokaryotes and viruses via a remarkable conformational transition. As with most sophisticated mechanisms, however, this is vulnerable to dysfunction. Pathogenic mutations result in the formation of serpin polymers, retained in the cell of synthesis. In these polymers the reactive loop of one molecule inserts as an extra ß-strand into a ß-sheet of the next. Polymerisation underlies a wide range of clinical diseases grouped together as the serpinopathies. I shall use crystallography and cryo-electron microscopy to define the pathways of polymerisation and to develop strategies to attenuate the ensuing disease. In particular I propose to i) determine the crystal structures of normal and abnormal conformers of neuroserpin associated with the dementia FENIB, ii) determine the structure of a serpin dimer: the basic unit of the toxic polymer, iii) define the structure of the serpin polymer using cryo-electron microscopy, and iv) determine the crystal structures of serpins bound to small molecules capable of blocking polymerisation.These approaches will provide information on how polymers form and how intermediates may be stabilised to ameliorate disease.