Danielle E. Chandler, Francois Penin, Klaus Schulten, and Christophe Chipot.
The p7 protein of hepatitis C virus forms structurally plastic,
minimalist ion channels.
PLoS Computational Biology, 8:e1002702, 2012.
(10 pages).
(PMC: 3447957)
CHAN2012A
Hepatitis C virus (HCV) p7 is a membrane-associated oligomeric protein harboring ion
channel activity. It is essential for selective assembly and release of infectious HCV
particles and an attractive target for antiviral intervention. Yet, the self-assembly and
molecular mechanism of p7 ion channelling are currently only partially understood. Using
molecular dynamics simulations (aggregate time 1.2 s), we show that p7 can form
stable
oligomers of four to seven subunits, with a bias towards six or seven subunits, and
suggest that p7 self-assembles in a sequential manner, with tetrameric and pentameric
complexes forming as intermediate states leading to the final hexameric or heptameric
assembly. We describe a
model of a hexameric p7 complex, which forms a transiently-open channel capable of
conducting ions in simulation. We investigate the ability of the hexameric model to flexibly
rearrange to adapt to the
local lipid environment, and demonstrate how this model can be reconciled with low-
resolution electron microscopy data. In the light of these results, a view of p7
oligomerization is proposed, wherein hexameric and heptameric complexes may coexist,
forming minimalist, yet robust functional ion channels. In the absence of a high-resolution
p7 structure, the models presented in this paper can prove valuable as a substitute
structure in future studies of p7 function, or in the search for p7-inhibiting drugs.
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