Dengue virus NS4A cytoplasmic domain binding to liposomes is sensitive to membrane curvatur

July 28, 2017

Title

Dengue virus NS4A cytoplasmic domain binding to liposomes is sensitive to membrane curvatur

Author

Yu-Fu Hung, Melanie Schwarten, Sven Schünke, Pallavi Thiagarajan-Rosenkranz, Silke Hoffmann, Ella H. Sklan, Dieter Willbold, Bernd W. Koenig

Year

2015

Journal

Biochimica et Biophysica Acta-Biomembranes

Abstract

Dengue virus (DENV) infection is a growing public health threat with more than one-third of the world's population at risk. Non-structural protein 4A (NS4A), one of the least characterized viral proteins, is a highly hydrophobic transmembrane protein thought to induce the membrane alterations that harbor the viral replication complex. The NS4A N-terminal (amino acids 1–48), has been proposed to contain an amphipathic α-helix (AH). Mutations (L6E; M10E) designed to reduce the amphipathic character of the predicted AH, abolished viral replication and reduced NS4A oligomerization. Nuclear magnetic resonance (NMR) spectroscopy was used to characterize the N-terminal cytoplasmic region (amino acids 1–48) of both wild type and mutant NS4A in the presence of SDS micelles. Binding of the two N-terminal NS4A peptides to liposomes was studied as a function of membrane curvature and lipid composition. The NS4A N-terminal was found to contain two AHs separated by a non-helical linker. The above mentioned mutations did not significantly affect the helical secondary structure of this domain. However, they reduced the affinity of the N-terminal NS4A domain for lipid membranes. Binding of wild type NS4A(1–48) to liposomes is highly dependent on membrane curvature.

Instrument

J-1100

Keywords

Circular dichroism, Vesicle interactions, Ligand binding, Secondary structure, Biochemistry