TY - JOUR
T1 - Structural and functional characterization of Reston Ebola virus VP35 interferon inhibitory domain
AU - Leung, Daisy W.
AU - Shabman, Reed S.
AU - Farahbakhsh, Mina
AU - Prins, Kathleen C.
AU - Borek, Dominika M.
AU - Wang, Tianjiao
AU - Mühlberger, Elke
AU - Basler, Christopher F.
AU - Amarasinghe, Gaya K.
N1 - Funding Information:
We thank the ISU Biotechnology Facilities and Dr. J. Hoy for providing access to instrumentation and support. We also thank P. Ramanan, J. Binning, L. Tantral, D. Peterson, and C. Brown for laboratory assistance, and Drs. S. Ginell, N. Duke, F. Rotella, M. Cuff, and J. Lazarz at APS Sector 19. Use of Argonne National Laboratory Structural Biology Center beamlines at the Advanced Photon Source was supported by the US Department of Energy under contract number DE-AC02-06CH11357 . This work was supported, in part, by National Institutes of Health grants ( 1F32AI084324 to D.W.L., 1F32AI084453 to R.S.S., R01AI059536 to C.F.B., and R01AI081914 to G.K.A.), by the German Research Foundation ( SFB 535 to E.M.), by MRCE Developmental Grant ( U54AI057160 -Virgin(PI) to G.K.A.), and by the Roy J. Carver Charitable Trust ( 09-3271 to G.K.A.).
PY - 2010/6
Y1 - 2010/6
N2 - Ebolaviruses are causative agents of lethal hemorrhagic fever in humans and nonhuman primates. Among the filoviruses characterized thus far, Reston Ebola virus (REBOV) is the only Ebola virus that is nonpathogenic to humans despite the fact that REBOV can cause lethal disease in nonhuman primates. Previous studies also suggest that REBOV is less effective at inhibiting host innate immune responses than Zaire Ebola virus (ZEBOV) or Marburg virus. Virally encoded VP35 protein is critical for immune suppression, but an understanding of the relative contributions of VP35 proteins from REBOV and other filoviruses is currently lacking. In order to address this question, we characterized the REBOV VP35 interferon inhibitory domain (IID) using structural, biochemical, and virological studies. These studies reveal differences in double-stranded RNA binding and interferon inhibition between the two species. These observed differences are likely due to increased stability and loss of flexibility in REBOV VP35 IID, as demonstrated by thermal shift stability assays. Consistent with this finding, the 1.71-Å crystal structure of REBOV VP35 IID reveals that it is highly similar to that of ZEBOV VP35 IID, with an overall backbone r.m.s.d. of 0.64 Å, but contains an additional helical element at the linker between the two subdomains of VP35 IID. Mutations near the linker, including swapping sequences between REBOV and ZEBOV, reveal that the linker sequence has limited tolerance for variability. Together with the previously solved ligand-free and double-stranded-RNA-bound forms of ZEBOV VP35 IID structures, our current studies on REBOV VP35 IID reinforce the importance of VP35 in immune suppression. Functional differences observed between REBOV and ZEBOV VP35 proteins may contribute to observed differences in pathogenicity, but these are unlikely to be the major determinant. However, the high level of similarity in structure and the low tolerance for sequence variability, coupled with the multiple critical roles played by Ebola virus VP35 proteins, highlight the viability of VP35 as a potential target for therapeutic development.
AB - Ebolaviruses are causative agents of lethal hemorrhagic fever in humans and nonhuman primates. Among the filoviruses characterized thus far, Reston Ebola virus (REBOV) is the only Ebola virus that is nonpathogenic to humans despite the fact that REBOV can cause lethal disease in nonhuman primates. Previous studies also suggest that REBOV is less effective at inhibiting host innate immune responses than Zaire Ebola virus (ZEBOV) or Marburg virus. Virally encoded VP35 protein is critical for immune suppression, but an understanding of the relative contributions of VP35 proteins from REBOV and other filoviruses is currently lacking. In order to address this question, we characterized the REBOV VP35 interferon inhibitory domain (IID) using structural, biochemical, and virological studies. These studies reveal differences in double-stranded RNA binding and interferon inhibition between the two species. These observed differences are likely due to increased stability and loss of flexibility in REBOV VP35 IID, as demonstrated by thermal shift stability assays. Consistent with this finding, the 1.71-Å crystal structure of REBOV VP35 IID reveals that it is highly similar to that of ZEBOV VP35 IID, with an overall backbone r.m.s.d. of 0.64 Å, but contains an additional helical element at the linker between the two subdomains of VP35 IID. Mutations near the linker, including swapping sequences between REBOV and ZEBOV, reveal that the linker sequence has limited tolerance for variability. Together with the previously solved ligand-free and double-stranded-RNA-bound forms of ZEBOV VP35 IID structures, our current studies on REBOV VP35 IID reinforce the importance of VP35 in immune suppression. Functional differences observed between REBOV and ZEBOV VP35 proteins may contribute to observed differences in pathogenicity, but these are unlikely to be the major determinant. However, the high level of similarity in structure and the low tolerance for sequence variability, coupled with the multiple critical roles played by Ebola virus VP35 proteins, highlight the viability of VP35 as a potential target for therapeutic development.
KW - Ebola VP35
KW - Immune evasion
KW - Viral protein structure
UR - http://www.scopus.com/inward/record.url?scp=77954757071&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2010.04.022
DO - 10.1016/j.jmb.2010.04.022
M3 - Article
C2 - 20399790
AN - SCOPUS:77954757071
SN - 0022-2836
VL - 399
SP - 347
EP - 357
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 3
ER -