Department of Biochemistry and Molecular Biology, Balylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Rotavirus is a major pathogen of infantile gastroenteritis. It is a large icosahedral virus with a complex architectural design capable of transcribing the genome endogenously. The genome of rotavirus consisting of eleven dsRNA segments encodes six structural and six non-structural proteins (NSPs). Subsequent to our previous cryo-EM studies which provided insights into structure, genome organization, cell entry, and mechanism of endogenous transcription in rotavirus, our present focus is on understanding the structural basis of its replication. The replication and packaging of rotavirus genome takes place in specialized compartments called viroplasms formed by two of the six non-structural proteins NSP2 and NSP5. NSP2 is a doughnut-shaped octamer with NTPase, ssRNA binding and helix destabilizing activities that are essential for genome replication/packaging. Using a combination of cryo-EM, X-ray crystallographic and biochemical techniques we have made inroads into understanding the structural basis of how this unique multifunctional protein may orchestrate rotavirus replication. The talk will focus on the recent X-ray crystallographic analysis of NSP2 with NTPs, which revealed a novel NDP kinase activity, and cryo-EM analysis of NSP2 bound toNSP5 and RNA at ∼8 Å resolution, which revealed that NSP5 may regulate the binding of RNA to NSP2.
