Conserved Determinants for Membrane Association of Nonstructural Protein 5A fromHepatitis C Virus and Related Viruses
- Brass, Volker Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany
- Pal, Zsuzsanna Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany
- Sapay, Nicolas Institut de Biologie et Chimie des Protéines, UMR 5086, CNRS, Université de Lyon, IFR 128 BioSciences Lyon-Gerland, F-69397 Lyon, France
- Deléage, Gilbert Institut de Biologie et Chimie des Protéines, UMR 5086, CNRS, Université de Lyon, IFR 128 BioSciences Lyon-Gerland, F-69397 Lyon, France
- Blum, Hubert E. Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany
- Penin, François Institut de Biologie et Chimie des Protéines, UMR 5086, CNRS, Université de Lyon, IFR 128 BioSciences Lyon-Gerland, F-69397 Lyon, France
- Moradpour, Darius Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, CH-1011 Lausanne, Switzerland
Published in:
- Journal of Virology. - American Society for Microbiology. - 2006, vol. 81, no. 6, p. 2745-2757
English
ABSTRACT
Nonstructural protein 5A (NS5A) is a membrane-associated essential component of the hepatitis C virus (HCV) replication complex. An N-terminal amphipathic
alpha helix mediates in-plane membrane association of HCV NS5A and at
the same time is likely involved in specific protein-protein
interactions required for the assembly of a functional replication
complex. The aim of this study was to identify the determinants for
membrane association of NS5A from the related GB viruses and
pestiviruses. Although primary amino acid sequences differed
considerably, putative membrane anchor domains with amphipathic
features were predicted in the N-terminal domains of NS5A proteins from
these viruses. Confocal laser scanning microscopy, as well as membrane
flotation analyses, demonstrated that NS5As from GB virus B (GBV-B),
GBV-C, and bovine viral diarrhea virus, the prototype pestivirus,
display membrane association characteristics very similar to those of
HCV NS5A. The N-terminal 27 to 33 amino acid residues of these NS5A
proteins were sufficient for membrane association. Circular dichroism
analyses confirmed the capacity of these segments to fold into alpha
helices upon association with lipid-like molecules. Despite structural
conservation, only very limited exchanges with sequences from related
viruses were tolerated in the context of functional HCV RNA
replication, suggesting virus-specific interactions of these segments.
In conclusion, membrane association of NS5A by an N-terminal
amphipathic alpha helix is a feature shared by HCV and related members
of the familyFlaviviridae . This observation points to
conserved roles of the N-terminal amphipathic alpha helices of NS5A in
replication complex
formation.
alpha helix mediates in-plane membrane association of HCV NS5A and at
the same time is likely involved in specific protein-protein
interactions required for the assembly of a functional replication
complex. The aim of this study was to identify the determinants for
membrane association of NS5A from the related GB viruses and
pestiviruses. Although primary amino acid sequences differed
considerably, putative membrane anchor domains with amphipathic
features were predicted in the N-terminal domains of NS5A proteins from
these viruses. Confocal laser scanning microscopy, as well as membrane
flotation analyses, demonstrated that NS5As from GB virus B (GBV-B),
GBV-C, and bovine viral diarrhea virus, the prototype pestivirus,
display membrane association characteristics very similar to those of
HCV NS5A. The N-terminal 27 to 33 amino acid residues of these NS5A
proteins were sufficient for membrane association. Circular dichroism
analyses confirmed the capacity of these segments to fold into alpha
helices upon association with lipid-like molecules. Despite structural
conservation, only very limited exchanges with sequences from related
viruses were tolerated in the context of functional HCV RNA
replication, suggesting virus-specific interactions of these segments.
In conclusion, membrane association of NS5A by an N-terminal
amphipathic alpha helix is a feature shared by HCV and related members
of the family
conserved roles of the N-terminal amphipathic alpha helices of NS5A in
replication complex
formation.
- Language
-
- English
- Open access status
- bronze
- Identifiers
-
- DOI 10.1128/jvi.01279-06
- ISSN 0022-538X
- Persistent URL
- https://sonar.ch/global/documents/210976
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