TY - JOUR
T1 - A Stable Prefusion Intermediate of the Alphavirus Fusion Protein Reveals Critical Features of Class II Membrane Fusion
AU - Sánchez-San Martín, Claudia
AU - Sosa, Hernando
AU - Kielian, Margaret
N1 - Funding Information:
This work was supported by grants to M.K. from the National Institute of Allergy and Infectious Diseases (R01-AI075647 and R21-AI067931) and by Cancer Center Core Support Grant NIH/NCI P30-CA13330. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Allergy and Infectious Diseases or the National Institutes of Health.
PY - 2008/12/11
Y1 - 2008/12/11
N2 - Alphaviruses infect cells via a low-pH-triggered membrane fusion reaction mediated by the class II virus fusion protein E1, an elongated molecule with three extramembrane domains (DI-III). E1 drives fusion by inserting its fusion peptide loop into the target membrane and refolding to a hairpin-like trimer in which DIII moves toward the target membrane and packs against the central trimer. Three-dimensional structures provide static pictures of prefusion and postfusion E1 but do not explain this transition. Using truncated forms of E1, we reconstituted a low-pH-dependent intermediate composed of trimers of DI/II. Unexpectedly, DI/II trimers were stable in the absence of DIII. Once formed at a low pH, DI/II trimers efficiently and specifically bound recombinant DIII through a pH-independent reaction. Even in the absence of DIII, DI/II trimers interacted to form hexagonal lattices and to cause membrane deformation and tubulation. These studies identify a prefusion intermediate in class II membrane fusion.
AB - Alphaviruses infect cells via a low-pH-triggered membrane fusion reaction mediated by the class II virus fusion protein E1, an elongated molecule with three extramembrane domains (DI-III). E1 drives fusion by inserting its fusion peptide loop into the target membrane and refolding to a hairpin-like trimer in which DIII moves toward the target membrane and packs against the central trimer. Three-dimensional structures provide static pictures of prefusion and postfusion E1 but do not explain this transition. Using truncated forms of E1, we reconstituted a low-pH-dependent intermediate composed of trimers of DI/II. Unexpectedly, DI/II trimers were stable in the absence of DIII. Once formed at a low pH, DI/II trimers efficiently and specifically bound recombinant DIII through a pH-independent reaction. Even in the absence of DIII, DI/II trimers interacted to form hexagonal lattices and to cause membrane deformation and tubulation. These studies identify a prefusion intermediate in class II membrane fusion.
KW - MICROBIO
UR - http://www.scopus.com/inward/record.url?scp=57049101667&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=57049101667&partnerID=8YFLogxK
U2 - 10.1016/j.chom.2008.10.012
DO - 10.1016/j.chom.2008.10.012
M3 - Article
C2 - 19064260
AN - SCOPUS:57049101667
SN - 1931-3128
VL - 4
SP - 600
EP - 608
JO - Cell Host and Microbe
JF - Cell Host and Microbe
IS - 6
ER -