Architecture of the hepatitis C virus E1 glycoprotein transmembrane domain studied by NMR

Hadas Zazrin, Hadassa Shaked, Jordan H. Chill

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Oligomerization of hepatitis C viral envelope proteins E1 and E2 is essential to virus fusion and assembly. Although interactions within the transmembrane (TM) domains of these glycoproteins have proven contributions to the E1/E2 heterodimerization process and consequent infectivity, there is little structural information on this entry mechanism. Here, as a first step towards our long-term goal of understanding the interaction between E1 and E2 TM-domains, we have expressed, purified and characterized E1-TM using structural biomolecular NMR methods. An MBP-fusion expression system yielded sufficient quantities of pure E1-TM, which was solubilized in two membrane-mimicking environments, SDS- and LPPG-micelles, affording samples amenable to NMR studies. Triple resonance assignment experiments and relaxation measurements provided information on the secondary structure and global fold of E1-TM in these environments. In SDS micelles E1-TM adopts a helical conformation, with helical stretches at residues 354-363 and 371-379 separated by a more flexible segment of residues 364-370. In LPPG micelles a helical conformation was observed for residues 354-377 with greater flexibility in the 366-367 dyad, suggesting LPPG provides a more native environment for the peptide. Replacement of key positively charged residue K370 with an alanine did not affect the secondary structure of E1-TM but did change the relative positioning within the micelle of the two helices. These results lay the foundation for structure determination of E1-TM and a molecular understanding of how E1-TM flexibility enhances its interaction with E2-TM during heterodimerization and membrane fusion.

Original languageEnglish
Pages (from-to)784-792
Number of pages9
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1838
Issue number3
DOIs
StatePublished - Mar 2014

Bibliographical note

Funding Information:
We gratefully acknowledge the ongoing support of Dr. Yoav Peleg (Weizmann Institute of Science, Rehovot, Israel) in design and cloning of E1-TM constructs, and thank Drs. Hugo Gottlieb and Keren Keinan-Adamsky and Mr. Israel Tabakman for technical support at the NMR facility. This work was supported in part by a research grant to J.H.C. by the Israel Science Foundation ( 801/09 ). The 700 MHz spectrometer was purchased with the support of the Converging Technologies Fund.

Keywords

  • Envelope glycoproteins
  • Hepatitis C virus
  • Membrane-associated proteins
  • Nuclear magnetic resonance
  • Protein structure
  • Transmembrane helix

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