Molecular architecture of the nucleoprotein C-terminal domain from the Ebola and Marburg viruses

The Filoviridae Filoviridae family of negative-sense, single-stranded RNA (ssRNA) viruses is comprised of two species ofMarburgvirus Marburgvirus (MARV and RAVV) and five species ofEbolavirus Ebolavirus,i.e. i.e. Zaire (EBOV), Reston (RESTV), Sudan (SUDV), Tai Forest (TAFV) and Bundibugyo (BDBV). In each of these viruses the ssRNA encodes seven distinct proteins. One of them, the nucleoprotein (NP), is the most abundant viral protein in the infected cell and within the viral nucleocapsid. It is tightly associated with the viral RNA in the nucleocapsid, and during the lifecycle of the virus is essential for transcription, RNA replication, genome packaging and nucleocapsid assembly prior to membrane encapsulation. The structure of the unique C-terminal globular domain of the NP from EBOV has recently been determined and shown to be structurally unrelated to any other known protein [Dziubaskaet al. et al. (2014),Acta Cryst Acta Cryst. D70 70, 2420-2429]. In this paper, a study of the C-terminal domains from the NP from the remaining four species ofEbolavirus Ebolavirus, as well as from the MARV strain ofMarburgvirus Marburgvirus, is reported. As expected, the crystal structures of the BDBV and TAFV proteins show high structural similarity to that from EBOV, while the MARV protein behaves like a molten globule with a core residual structure that is significantly different from that of the EBOV protein.