Hydrophobic segment of dengue virus C protein. Interaction with model membranes

Figures & data

Figure 1. (A) Scheme indicating the position of the domain corresponding to DENV2_C6 peptide on the DENVC structure (grey shading). The dimer of DENVC has been represented (Ma et al. 2004). (B) Fluorescence signal amplitude of FPE versus peptide concentration in μM to determine DENV2_C6 peptide binding to membrane model systems with different lipid compositions. The lipid compositions used were EPC (▪), EPC/CHOL at a molar ratio of 5:1 (○), EPC/ESM/CHOL at a molar ratio of 5:2:1 (□), EPC/EPA at a molar ratio of 5:2 (•), EPC/BPS at a molar ratio of 5:2 (▴) and synthetic ER membranes (Δ).The lipid concentration was 200 μM. Vertical bars indicate standard deviations of the mean of triplicate samples.

Figure 2. Effect of the DENV2_C6 peptide on the release (membrane rupture) of CF (A, B, C and D), FD20 (E) and FD70 (F) for general different lipid compositions (A, B, E and F), lipid compositions containing different molar ratios of EPC, ESM and Chol (C) and the ER^58:6 complex lipid mixture and its variations (D). In (A), model membranes with the following lipid compositions are shown: EPC (▪), EPC/EPA in a molar proportion of 5:2 (•), EPC BPS at a molar ratio of 5:2 (▴), total lipid liver extract (▾), ER-like membranes (◂), and EPC/BMP at a molar ratio of 5:2 (⧫). In (B), the following model membranes are shown: EPC/CHOL at a molar ratio of 5:1 (▪), EPC/CHOL at a molar ratio of 5:2 (▴), EPC/CHOL at a molar ratio of 5:3 (▴), EPC/EPA/CHOL at a molar ratio of 5:2:1 (▾) and EPC/BPS/CHOL at a molar ratio of 5:2:1 (◂). In (C), the following model membranes are shown: EPC/ESM/CHOL at a molar ratio of 5:1:1 (▪), EPC/ESM/CHOL at a molar ratio of 5:2:1 (▴), EPC/ESM/CHOL at a molar ratio of 5:3:1 (▴), EPC/ESM/CHOL at a molar ratio of 5:2:2 (▾) and EPC/ESM at a molar ratio of 5:2 (♦). In (D), the following model membranes are shown: ER ^58:6 (x), ER^58:6 minus Chol (▴), ER^58:6 minus BPI (▾), ER^58:6 minus TPE (♦), ER^58:6 minus ESM (▴), ER^58:6 minus BPS (◂), ER^58:6 minus EPA (◊) and ER^58:6 minus CL (▸). The lipid compositions of the model membranes used to study the release of FD20 (E) and FD70 (F) were: EPC (▪), EPC/CHOL in a molar proportion 5:1 (▴), EPC/ESM/CHOL in a molar proportion 5:2:1 (▴), EPC/EPA in a molar proportion 5:2 (▾), EPC/BPS in a molar proportion 5:2 (◂) and ER-like membranes (▸). Vertical bars indicate standard deviations of the mean of triplicate samples.

Figure 3. Steady-state anisotropy, <r>, of TMA-DPH and DPH (left and right columns, respectively) incorporated into MLVs composed of DMPC (A and B), DMPG (C and D), DMPS (E and F), DMPA (G and H), DPPC (I and J), DSPC (K and L), and 14BMP (M and N) model membranes as a function of temperature. Data correspond to vesicles in the absence (▪) and presence of the DENV2_C6 peptide (○). The peptide to phospholipid molar ratio was 1:15.

Figure 4. Differential scanning calorimetry heating thermograms corresponding to model membranes composed of (A) DMPC, (B) DEPE, (C) DMPS, (D) DMPA, (E) DMPG, (F) 14BMP and (G) PSM in the absence (top curves) and presence of DENV2_C6 peptide (bottom curves) at a phospholipid/peptide molar ratio of 15:1. All the thermograms were normalized to the same amount of lipid.

Figure 5. Stacked infrared spectra of the C = O and Amide I' regions of DENV2_C6 (A) in solution and in the presence of (B) DMPC, (C) DMPG, (D) DMPG and (E) 14BMP at different temperatures as indicated. The pure phospholipid is shown on the left whereas the phospholipid/peptide mixture is shown on the right. The temperature dependence of the frequency at the maximum of the Amide I' region of DENV2_C6 in solution (□) and the intensity ratio of the 1684 cm^-1 and 1694 cm^-1 bands (▪) are shown in the upper right figure. The phospholipid/peptide molar ratio was 15:1.

Figure 6. Temperature dependence of the frequencies of the (A, B, C) C = O carbonyl and (D, E, F) CH₂ symmetric stretching bands for samples of (A, D) DMPC, (B, E) DMPG and (C, F) 14BMP in the pure form (▪) and in the presence of the DENV2_C6 peptide (○). The phospholipid/peptide molar ratio was 15:1.

Table I. Alignment (ClustalW2) of DENV2_C6 peptide from reference strains representing the major genotypes of Dengue virus. The DENV2_C6 and consensus sequences are shown beneath the alignment.

DENV	Strain	Sequence	DENV	Strain	Sequence
Type 2	MD917	GRGPLKLFMALVAFLRFL	Type 3	C036094-C	GQGPMKLVMAFIAFLRFL
	BIDV687	GRGPLKLFMALVAFLRFL		ThD31283_98-C	GQGPMKLVMAFIAFLRFL
	MD903	GRGPLKLFMALVTFLRFL		BIDV1831VN2007-C	GQGPMKLVMAFIAFLRFL
	BIDV633	GHGPLKLFMALVAFLRFL		07CHLS001-C	GQGPMKLVMAFIAFLRFL
	CSF381-C	GRGPLKLFMALVAFLRFL		BIDV1874VN2007-C	GQGPMKLVMAFIAFLRFL
	MD1504	GRGPLKLFMALVAFLRFL		05K797DK1-C	GQGPMKLVMAFIAFLRFL
	CSF63-C	GRGPLKLFMALVAFLRFL		98TWmosq-C	GQGPMKLVMAFIAFLRFL
	DakArD20761	GRGPLKLFMALVAFLRFL		BR29002-C	GQGPMKLVMAFIAFLRFL
	DF755-C	GRGPLKLFMALVAFLRFL		98-C	GQGPMKLVMAFIAFLRFL
	DF707	GRGPLKLFMALVAFLRFL		TB55i-C	GQGPMKLVMAFIAFLRFL
Type 1	02_20-C	GQGPMKLVMAFIAFLRFL	Type 4	2A-C	GKGPLRMVLAFITFLRVL
	ThD1004901-C	GQGPMKLVMAFIAFLRFL		BIDV2165VE1998-C	GKGPLRMVLAFITFLRVL
	BIDV1841-C	GQGPMKLVMAFIAFLRFL		BIDV2170VE1999-C	GKGPLRMVLAFITFLRVL
	BIDV1926VN2008	GQGPMKLVMAFIAFLRFL		Vp4-C	GKGPLRMVLAFITFLRVL
	BIDV1800	GQGPMKLVMAFIAFLRFL		Yama-C	GKGPLRMVLAFITFLRVL
	BIDV1323	GQGPMKLVMAFIAFLRFL		Sin897695-C	GKGPLRMVLAFITFLRVL
	BIDV2243VE2007	GQGPMKLVMAFIAFLRFL		rDEN4del30-C	GKGPLRMVLAFITFLRVL
	05K4147DK1	GQGPMKLVMAFIAFLRFL		H241-C	GKGPLRMVLAFITFLRVL
	297arg00	GQGPMKLVMAFIAFLRFL		ThD4048501-C	GKGPLRMVLAFITFLRVL
	BIDV2143-C	GQGPMKLVMAFIAFLRFL		ThD4047697-C	GKGPLRMVLAFITFLRVL
	Consensus sequence	*:**:::.:*:::***.*
	PEPTIDE DENV2C6	GRGPLKLFMALVAFLRFL

Ma L, Jones CT, Groesch TD, Kuhn RJ, Post CB. 2004. Solution structure of dengue virus capsid protein reveals another fold. Proc Natl Acad Sci USA 101:3414–3419.

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