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

• Published in: Biochimica et biophysica acta Vol. 1848; no. 5; pp. 1119 - 1126
• Main Authors: Hung, Yu-Fu, Schwarten, Melanie, Schünke, Sven, Thiagarajan-Rosenkranz, Pallavi, Hoffmann, Silke, Sklan, Ella H., Willbold, Dieter, Koenig, Bernd W.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2015
• Subjects: Amphipathic helix; Circular Dichroism; Curvature sensing; Dengue virus; Dengue Virus - growth & development; Dengue Virus - metabolism; Liposomes; Membrane Lipids - chemistry; Membrane Lipids - metabolism; Micelles; Mutation; NMR spectroscopy; Non-structural protein NS4A; Nuclear Magnetic Resonance, Biomolecular; Peptide membrane interaction; Protein Binding; Protein Multimerization; Protein Structure, Secondary; Protein Structure, Tertiary; Structure-Activity Relationship; Surface Plasmon Resonance; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - metabolism; Virus Replication; CD; NS4A(1–48); RU; NOE; AH; DLS; TLC; Dengue virus; ER; Amphipathic helix; Peptide membrane interaction; NMR; Non-structural protein NS4A; SPR; SUV; DENV; NS4A; Curvature sensing; RCI; HCV; NMR spectroscopy; pTMS
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2015.01.015

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. [Display omitted] •NS4A(1–48) and peptide from replication deficient mutant are characterized.•NMR backbone assignments and peptide secondary structures in micelles are reported.•Both wild type and mutant peptides contain two amphipathic helices.•Wild type NS4A(1–48) shows stronger binding to liposomes compared to the mutant.•NS4A(1–48) binds preferentially to highly curved lipid membranes.