Visualization of membrane protein domains by cryo-electron microscopy of dengue virus.
Improved technology for reconstructing cryo-electron microscopy (cryo-EM) images has now made it possible to determine secondary structural features of membrane proteins in enveloped viruses. The structure of mature dengue virus particles was determined to a resolution of 9.5 A by cryo-EM and image reconstruction techniques, establishing the secondary structural disposition of the 180 envelope (E) and 180 membrane (M) proteins in the lipid envelope. The alpha-helical 'stem' regions of the E molecules, as well as part of the N-terminal section of the M proteins, are buried in the outer leaflet of the viral membrane. The 'anchor' regions of E and the M proteins each form antiparallel E-E and M-M transmembrane alpha-helices, leaving their C termini on the exterior of the viral membrane, consistent with the predicted topology of the unprocessed polyprotein. This is one of only a few determinations of the disposition of transmembrane proteins in situ and shows that the nucleocapsid core and envelope proteins do not have a direct interaction in the mature virus.
Zhang
Wei
W
Department of Biological Sciences, Lilly Hall, 915 W. State Street, Purdue University, West Lafayette, Indiana 47907, USA.
Chipman
Paul R
PR
Corver
Jeroen
J
Johnson
Peter R
PR
Zhang
Ying
Y
Mukhopadhyay
Suchetana
S
Baker
Timothy S
TS
Strauss
James H
JH
Rossmann
Michael G
MG
Kuhn
Richard J
RJ
D020285:Cryoelectron Microscopy; D003716:Dengue Virus / Q000378:metabolism / Q000648:ultrastructure*; D019251:Nucleocapsid / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014763:Viral Matrix Proteins / Q000378:metabolism / Q000648:ultrastructure*
D014763:Viral Matrix Proteins