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Interaction of Dengue Fusion Peptideswith model membrane systems

Danilo OlivierAmando Ito

April 16, 2015

Danilo Olivier Amando Ito Dengue Peptides in interaction with model membrane

Dengue Fever and Dengue Virus

I Aedes aegyptiI Size: 50nmI Flaviviruses, Yellow FeverI 4 Different Serotypes

1

1Source: The Journal of General Virology, 87(Pt 10), 2755–66, (2006).


Infection and Fusion Process

Figure : Mechanism of fusion.2

I EndocytosisI Virus mature in low pHI Fusion Peptide is exposed

2Source: The Journal of General Virology, 87(Pt 10), 2755–66, (2006).


Viral Fusion Peptide and Membrane Models

Peptides:I Putative Fusion Peptide: DEN II.98-112I Large Sequence: DEN II.88-123

KRFVC KHSMV DRGWG NGCGL FGKGG IVTCA MFTCKK

Figure : Top: Dengue Peptide in NewCartoon and Tryptophan in CPK representation. Bottom: Dengue VirusPeptide sequence. Charged polar (green), Hydrophobic (blue) and non-charged polar (red). PDB Code:1OK8.

Models:I Large Unilamellar Vesicles (Experiments) - Lipid Bilayers (In Silico Experiments)I Lipids: DMPC, DMPG


MD: DEN II.88-123 in interaction with DMPC bilayer


MD: Equilibrium of DMPC bilayer

Figure : RMSD of the system during the simulation.


MD: Root Mean Square Fluctuation

90 100 110 120Residue Number

0

5

10

15

RM

SF

(nm

)DEN.II 88-123DEN.II 88-123 + DMPC

Figure : Root mean square fluctuation in solution and DMPC.


MD: Electronic Density Profile

0

0,1

0,2

0,3

0,4

0,5

Den

sity

( e

- / Å 3 )

TotalDMPCWaterPeptideTrp

-40 -20 0 20 40z-Axis ( Å )

0

0,00050,001


MD: Order Parameter

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Carbon Atom Number ( # )

0

0,05

0,1

0,15

0,2

0,25

|SC

D|

DMPCDMPC + Pep

Figure : Order Parameter after 180ns of simulation.


MD: Area per lipid

0 20 40 60 80 100 120 140 160 180Time (ns)

54

56

58

60

62

64

66

68

Are

a (Å

2 )

Figure : Area per lipid during the simulation.


MD/FLU: Anisotropy and Rotational Correlation

A = A1 ∗ exp(−x/θ1) + A2 ∗ exp(−x/θ2) + A∞ (1)

Table : Comparison between exponential fit for fluorecence anisotropy and rotationalcorrelation for Trp.

System Fit A1 θ1(ns) A2 θ2(ns) A∞

DEN II.88-123 Exp. 0,11 0,35 0,02 2,03 -0,018Comp. 0,12 0,35 0,15 3,70 -0,001

DEN II.88-123 + DMPC Exp. 0,21 0,04 0,11 0,33 0,018Comp. 0,15 0,59 0,17 3,06 -0,001

Table : Steady state anisotropy.

88 - 123ABuffer 0.021ADMPC 0.034


MD/FLU: Secondary Structure of DEN II.88-123 during interaction with DMPC

bilayer.

Figure : Secondary Structure colors: Yellow: Coil, Orange: Bridge, Purple: Extented,Green: Turn, Blue: 3-10 Helix.


Final Configuration


Preliminary Conclusions

I Peptide interacts with lipid bilayer;I No significant changes in the lipid bilayer;I Differences in fluorecence anysotropy decay of Trp;I Low agreement between experiment - simulation for the

anisotropy in DMPC;I DEN II.88-123 in membrane is hindered compare with peptide

in solution;


Acknowledgement

I USP - Universidade de São PauloI Rice UniversityI CNPq
