Structural and functional studies of enterovirus 2C proteins: promising targets for antiviral therapy.

ended

The enterovirus (EV) genus comprises many important human pathogens including poliovirus, coxsackieviruses, EV-A71, EV-D68 and rhinoviruses. These viruses are responsible for a wide array of diseases ranging from mild to life-threatening, such as neonatal sepsis and paralysis. There are hundreds of enteroviruses, and vaccination to all of these is not a viable option. As such, there is an urgent requirement for effective broad-spectrum antivirals. Enterovirus genomes comprise a positive-sense ssRNA genome which encodes four structural proteins (VP1--4) and seven non-structural proteins (2A--C, 3A--D). The non-structural proteins 2B, 2C and 3A cooperatively hijack host cell proteins and alter host cell membranes and lipid homeostasis to generate membranous replication organelles, which serve as platforms for genome replication and virion morphogenesis. The 2C protein is a particularly attractive target for the development of antivirals due to its high level of sequence conservation. 2C is an AAA+ ATPase with many proposed functions within the virus lifecycle including helicase activity, reorganisation of cellular membranes and encapsidation. Several structurally disparate drugs target 2C on the basis that resistance mutations map to this protein; however, the molecular basis of their effect on 2C is not understood. This project has two main objectives: 1. Determine the high-resolution structure of the functional hexameric 2C and inhibitor/ligand complexes by cryo-electron microscopy. 2. Use cryo-electron tomography to characterise the interactions 2C makes with viral and host proteins within ex-vivo and in situ replication organelles. Understanding the organisation of 2C within replication organelles will shed new light on its role in the enterovirus life cycle, and the high-resolution structure of 2C will serve as a long sought-after search template for structure-based drug design of urgently-needed anti-enteroviral drugs.