[NMR paper] The Three Dimensional Structure and Interaction Studies of HCV p7 in DHPC by Solution NMR.

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The Three Dimensional Structure and Interaction Studies of HCV p7 in DHPC by Solution NMR.

The Three Dimensional Structure and Interaction Studies of HCV p7 in DHPC by Solution NMR.

Biochemistry. 2013 Jul 10;

Authors: Cook GA, Dawson LA, Tian Y, Opella SJ

Abstract
Hepatitis C Virus (HCV) protein p7 plays an important role in the assembly and release of mature virus particles. This small 63-residue membrane protein has been shown to induce channel activity, which may contribute to its functions. p7 is highly conserved throughout the entire range of HCV genotypes, which contributes to making p7 a potential target for anti-viral drugs. The secondary structure of p7 from the J4 genotype and the tilt angles of the helices within bilayers have been previously characterized by NMR. Here we describe the three-dimensional structure of p7 in short chain phospholipid (DHPC) micelles, which provide a reasonably effective membrane-mimicking environment that is compatible with solution NMR experiments. Using a combination of chemical shifts and residual dipolar couplings we determined the structure of p7 using an implicit membrane potential combining both CS-Rosetta decoys and Xplor-NIH refinement. The final set of structures has a backbone RMSD of 2.18 Å. Molecular dynamic simulations in NAMD indicate that several side chain interactions might be taking place, and that these could affect the dynamics of the protein. In addition to probing the dynamics of p7, several drug-protein and proteinprotein interactions were evaluated. Established channel-blocking compounds such as amantadine, hexamethylene amiloride (HMA), and long alkyl-chain iminosugar derivatives inhibit the ion channel activity of p7. It has also been shown that the protein interacts with the HCV non-structural protein 2 (NS2) at the endoplasmic reticulum, and that this interaction may be important for the infectivity of the virus. Changes in the chemical shift frequencies of solution NMR spectra identify the residues taking part in these interactions.


PMID: 23841474 [PubMed - as supplied by publisher]



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