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Title: Two different conformations in hepatitis C virus p7 protein account for proton transport and dye release
Authors: Gan, Siok Wan
Surya, Wahyu
Vararattanavech, Ardcharaporn
Torres, Jaume
Keywords: DRNTU::Science::Biological sciences::Molecular biology
Issue Date: 2014
Source: Gan, S. W., Surya, W., Vararattanavech, A., & Torres, J. (2014). Two Different Conformations in Hepatitis C Virus p7 Protein Account for Proton Transport and Dye Release. PLoS ONE, 9(1), e78494-.
Series/Report no.: PLoS ONE
Abstract: The p7 protein from the hepatitis C virus (HCV) is a 63 amino acid long polypeptide that is essential for replication, and is involved in protein trafficking and proton transport. Therefore, p7 is a possible target for antivirals. The consensus model for the channel formed by p7 protein is a hexameric or heptameric oligomer of α-helical hairpin monomers, each having two transmembrane domains, TM1 and TM2, where the N-terminal TM1 would face the lumen of this channel. A reported high-throughput functional assay to search for p7 channel inhibitors is based on carboxyfluorescein (CF) release from liposomes after p7 addition. However, the rationale for the dual ability of p7 to serve as an ion or proton channel in the infected cell, and to permeabilize membranes to large molecules like CF is not clear. We have recreated both activities in vitro, examining the conformation present in these assays using infrared spectroscopy. Our results indicate that an α-helical form of p7, which can transport protons, is not able to elicit CF release. In contrast, membrane permeabilization to CF is observed when p7 contains a high percentage of β-structure, or when using a C-terminal fragment of p7, encompassing TM2. We propose that the reported inhibitory effect of some small compounds, e.g., rimantadine, on both CF release and proton transport can be explained via binding to the membrane-inserted C-terminal half of p7, increasing its rigidity, in a similar way to the influenza A M2-rimantadine interaction.
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0078494
Rights: © 2014 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Fulltext Permission: open
Fulltext Availability: With Fulltext
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