Unlike dengue virus, the conserved 14–23 residues in N-terminal region of Zika virus capsid is not involved in lipid interactions

https://doi.org/10.1016/j.bbamem.2020.183440Get rights and content
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Highlights

  • Capsid N-terminal regions 1-30 and 5-26, undergo disorder-to-order transition in the presence of TFE, SDS and liposomes.

  • The conserved region (14-23) of ZIKV-C does not undergo any conformational change.

  • Unlike DENV, the 14-23 conserved region may not be involved in the lipid interactions in ZIKV-C.

  • The lipid interacting motif of ZIKV-C N-terminal may span the region between residues 24-30.

Abstract

Zika virus capsid protein is involved in multiple essential steps of the viral life cycle. Many vital functionalities are attributed to the dynamic N- terminal domain of this protein, which is intrinsically disordered in ZIKV and among several flaviviruses too. Other than genome encapsulation, studies have shown interaction with host lipid droplets to be crucial for replication and maturation. In Dengue virus, the molecular basis of such interplay has been studied in detail, and residues within the capsid N-terminal disordered domain has been mapped. It revealed a new function of a conserved region in mediating capsid-lipid droplet association through a conformational transition. Therefore, in this study, we attempt to analyze the structural dynamics of Zika virus capsid's N- terminal domain and analyzed it through a reductionist approach by dividing the N-terminal domain into three truncated segments and studied them individually. Techniques such as Circular dichroism spectroscopy, Dynamic light scattering, Zeta potential and Molecular dynamic simulations were employed to identify the motif responsible for structural flexibility and ability to interact with membrane models. Our results confirm that the truncated segments 5–26 and 1–30 readily adopt an α-helical conformation in the presence of 2,2,2-trifluoro-ethanol, detergent and negatively charged phospholipids. However, in contrast to Dengue virus, we report the conserved residues 14–23 region to be unstructured and do not undergo a conformational switch in Zika virus. Thus, our study illustrates the possibility of conserved 14–23 region's non-involvement in ZIKV capsid-lipid droplet association, unlike DENV.

Abbreviations

ZIKV
Zika virus
DENV
dengue virus
BVDV
Bovine viral diarrhea virus
TFE
2,2,2-trifluoro-ethanol
SDS
sodium dodecyl sulfate
LD
lipid droplet
DLS
dynamic light scattering
SLEV
Saint Louis encephalitis virus
JEV
Japanese encephalitis virus
WNV
West Nile virus
YFV
Yellow fever virus
RNA
Ribonucleic acid
IDD/P
intrinsically disordered domain/protein C-LD: Capsid-Lipid droplet interaction
CD
circular dichroism
MD
molecular dynamics
NMR
Nuclear Magnetic Resonance
DOPC
1,2-dioleoyl-sn-glycero-3-phosphocholine
DOPS
1,2-dioleoyl-sn-glycero-3-phospho-l-serine
LUV
large unilamellar vesicles

Keywords

Zika virus
Intrinsically disordered protein
Capsid
Liposomes
Zeta potential

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