Hwankyu Lee

Dankook University, Eidō, Chungcheongbuk-do, South Korea

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Publications (42)167.26 Total impact

  • Hwankyu Lee
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    ABSTRACT: Imidazolium-based ionic surfactants of different sizes were simulated with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers. Regardless of the phospholipid type, larger surfactants at higher concentrations more significantly insert into the bilayer and increase the bilayer-surface size, in agreement with experiments and previous simulations. Insertion of surfactants only slightly decreases the bilayer thickness, as also observed in experiments. Although the surfactant insertion and its effect on the bilayer size and thickness are similar in different types of bilayers, the volume fractions of surfactants in the bilayer are higher for DMPC bilayers than for POPC and DOPC bilayers. In particular, ionic surfactants with four hydrocarbons yield their volume fractions of 4.6% and 8.7%, respectively, in POPC and DMPC bilayers, in quantitative agreement with experimental values of ∼5% and ∼10%. Also, the inserted surfactants increase the lateral diffusivity of the bilayer, which depends on the bilayer type. These findings indicate that although the surfactant insertion does not depend on the bilayer type, the effects of surfactants on the volume fraction and bilayer dynamics occur more significantly in the DMPC bilayer because of the smaller area per lipid and shorter saturated tails, which helps explain the experimental observations regarding different volume fractions of surfactants in POPC and DMPC bilayers. Copyright © 2015 Elsevier Inc. All rights reserved.
    Journal of Molecular Graphics and Modelling 05/2015; DOI:10.1016/j.jmgm.2015.05.010 · 2.02 Impact Factor
  • Eol Han, Hwankyu Lee
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    ABSTRACT: We performed coarse-grained molecular dynamics simulations of tachyplesin I (TP-I), which is a β-hairpin antimicrobial peptide with two disulfide bonds, and its linearly extended derivative without disulfide bonds (TPA4) in lipid bilayers for 5μs. β-hairpin TP-I peptides tend to individually bind to the bilayer surface, while linear TPA4 peptides aggregate and form the β-strand complex on the bilayer surface, indicating the effect of the peptide structure on aggregation. Also, TPA4 more slowly diffuse along the bilayer surface than do TP-I, indicating that aggregated β-strands of TPA4 cannot diffuse as fast as individual β-hairpins of TP-I. TPA4 have the stronger charge interaction with lipid head groups than do TP-I, leading to the deeper insertion into the bilayer. These simulation results indicate that TP-I peptides tend to individually exist on the bilayer surface and thus easily diffuse along the bilayer surface, while TPA4 peptides aggregate as β-strands, which limits the lateral mobility of TPA4, leading to a strong immobilization of TPA4. These findings agree well with the experimentally observed dependence of peptide mobility on the peptide structure in membranes, as well as support experimental suggestions regarding the formation of β-strand complexes of linear TPA4 and the relationship between the peptide aggregation and mobility. Copyright © 2015 Elsevier Inc. All rights reserved.
    Journal of Molecular Graphics and Modelling 04/2015; 59. DOI:10.1016/j.jmgm.2015.04.007 · 2.02 Impact Factor
  • Biophysical Journal 01/2015; 108(2):384a-385a. DOI:10.1016/j.bpj.2014.11.2108 · 3.83 Impact Factor
  • Sun Young Woo, Hwankyu Lee
    Biophysical Journal 01/2015; 108(2):466a. DOI:10.1016/j.bpj.2014.11.2544 · 3.83 Impact Factor
  • Hwankyu Lee, Tae-Joon Jeon
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    ABSTRACT: Imidazolium-based ionic surfactants with hydrocarbon tails of different sizes were simulated with lipid bilayers at different salt concentrations. Starting with the random position of ionic surfactants outside the bilayer, surfactants with long tails mostly insert into the bilayer, while those with short tails show the insertion of fewer surfactant molecules, indicating the effect of the tail length. In particular, surfactants with the tail of two or four hydrocarbons insert and reversibly detach from the bilayer, while the inserted longer surfactants cannot be reversibly detached because of the strong hydrophobic interaction with lipid tails, in quantitative agreement with experiments. Longer surfactants more deeply and irreversibly insert into the bilayer and thus increase lateral diffusivities of the bilayer, indicating that longer surfactants more significantly disorder lipid bilayers, which also agrees with experiments regarding the effect of the tail length of ionic surfactants on membrane permeability and toxicity. Addition of NaCl ions weakens the electrostatic interactions between head groups of surfactants and lipids, leading to the binding of fewer surfactants into the bilayer. In particular, our simulation findings indicate that insertion of ionic surfactants can be initiated by either the hydrophobic interaction between tails of surfactants and lipids or the electrostatic binding between imidazolium heads and lipid heads, and the strength of hydrophobic and electrostatic interactions depends on the tail length of surfactants.
    Physical Chemistry Chemical Physics 01/2015; 17(8). DOI:10.1039/C4CP05537C · 4.20 Impact Factor
  • Eol Han, Hwankyu Lee
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    ABSTRACT: We performed coarse-grained molecular dynamics simulations of antimicrobial peptides PGLa and magainin 2 in lipid bilayers. PGLa peptides or mixtures of PGLa and magainin 2 were initially widely spaced or clustered above the bilayer surface with different heterodimeric orientations (parallel or antiparallel). Simulations show that the presence of magainin 2 promotes more tilting and insertion of PGLa into the bilayer, indicating the synergistic effect. Magainin 2 interact with lipid headgroups and thus stay horizontally on the bilayer surface, while PGLa insert into the bilayer, leading to more tilted conformation, in agreement with recent NMR experiments. In particular, for the systems with the initially antiparallel-oriented heterodimers or with the neutrally mutated magainin 2, much fewer parallel heterodimers form, and PGLa peptides are less tilted and inserted, indicating that the formation of parallel heterodimers is important for the PGLa insertion, as suggested in experiments. Peptides aggregate in the mixture of PGLa and magainin 2, but not in the system without magainin 2, indicating that magainin 2 induce the peptide aggregation, which is required for the pore formation. These simulation findings agree with the experimental observations of the heterodimer formation as well as different positions of PGLa and magainin 2 in the bilayer, which seem to conflict. These conflicting results can be explained by the synergistic mechanism that magainin 2 form parallel heterodimers with PGLa and induce the aggregation of heterodimers, leading to the formation of pores, where magainin 2 tend to interact with the bilayer surface, while PGLa are tilted and inserted into the hydrophobic region of the bilayer.
    RSC Advances 12/2014; 5(3). DOI:10.1039/C4RA08480B · 3.71 Impact Factor
  • Source
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    ABSTRACT: One application of nanotechnology in medicine that is presently being developed involves a drug delivery system (DDS) employing nanoparticles to deliver drugs to diseased sites in the body avoiding damage of healthy tissue. Recently, the mild hyperthermia-triggered drug delivery combined with anticancer agent-loaded thermosensitive liposomes was widely investigated. In this study, thermosensitive liposomes (TSLs), composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-PEG), cholesterol, and a fatty acid conjugated elastin-like polypeptide (ELP), were developed and optimized for triggered drug release, controlled by external heat stimuli. We introduced modified ELP, tunable for various biomedical purposes, to our thermosensitive liposome (e-TSL) to convey a high thermoresponsive property. We modulated thermosensitivity and stability by varying the ratios of e-TSL components, such as phospholipid, ELP, and cholesterol. Experimental data obtained in this study corresponded to results from a simulation study that demonstrated, through the calculation of the lateral diffusion coefficient, increased permeation of the lipid bilayer with higher ELP concentrations, and decreased permeation in the presence of cholesterol. Finally, we identified effective drug accumulation in tumor tissues and antitumor efficacy with our optimized e-TSL, while adjusting lag-times for systemic accumulation.
    PLoS ONE 07/2014; 9(7):e103116. DOI:10.1371/journal.pone.0103116 · 3.53 Impact Factor
  • Sun Young Woo, Hwankyu Lee
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    ABSTRACT: We performed coarse-grained (CG) molecular dynamics simulations of trimeric α-helical coiled coils grafted with polyethylene glycol (PEG) of different sizes and conjugate positions, and the self-assembled micelle of amphiphilic trimers. The CG model for the trimeric coiled coil is verified by comparing the α-helical structure and interhelical distance with those calculated from all-atom simulations. In CG simulations of PEGylated trimers, end-to-end distances and radii of gyration of PEGs grafted to the side of peptides become smaller than those of free PEGs in water, which agree with experiments. This smaller size of the grafted PEGs is also confirmed by calculating the thickness of the PEG layer, which is smaller than the size of the mushroom. These indicate the adsorption of PEG chains onto coiled coils, since hydrophobic residues in the exterior sites of coiled coils tend to be less exposed to water and thus interact with PEGs, leading to the compact conformation of adsorbed PEGs. Simulations of the self-assembly of amphiphilic trimers show that the randomly distributed trimers self-assemble to micelles. The outer radius and hydrodynamic radius of the micelle, which were calculated respectively from radial densities and diffusion coefficients, are ~7 nm, in agreement with the experimental value of ~7.5 nm, while the aggregation number of amphiphilic molecules per micelle is lower than the experimentally proposed value. These simulations predict the experimentally measured size of PEGs grafted to the trimeric coiled coils and their self-assembled amphiphilic micelles, as well as suggest that the aggregation number of the micelle may be smaller, which needs to be confirmed by experiments.
    Langmuir 07/2014; 30(29). DOI:10.1021/la501973w · 4.38 Impact Factor
  • Hwankyu Lee
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    ABSTRACT: Polyethylene glycol (PEG) has been conjugated to many drugs or drug carriers to increase their solubility and circulating lifetime, and reduce toxicity. This has motivated many experimental studies to understand the effect of PEGylation on delivery efficiency. To complement the experimental findings and uncover the mechanism that cannot be captured by experiments, all-atom and coarse-grained molecular dynamics (MD) simulations have been performed. This has become possible, due to recent advances in simulation methodologies and computational power. Simulations of PEGylated peptides show that PEG chains wrap antimicrobial peptides and weaken their binding interactions with lipid bilayers. PEGylation also influences the helical stability and tertiary structure of coiled-coil peptides. PEGylated dendrimers and single-walled carbon nanotubes (SWNTs) were simulated, showing that the PEG size and grafting density significantly modulate the conformation and structure of the PEGylated complex, the interparticle aggregation, and the interaction with lipid bilayers. In particular, simulations predicted the structural transition between the dense core and dense shell of PEGylated dendrimers, the phase behavior of self-assembled complexes of lipids, PEGylated lipids, and SWNTs, which all favorably compared with experiments. Overall, these new findings indicate that simulations can now predict the experimentally observed structure and dynamics, as well as provide atomic-scale insights into the interactions of PEGylated complexes with other molecules.
    Polymers 03/2014; 6(3):776-798. DOI:10.3390/polym6030776 · 2.51 Impact Factor
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    ABSTRACT: Lipid bilayers, which consist of dipalmitoylglycerophosphocholines (DPPCs), PEGylated lipids, cholesterols, and elastin-like polypeptides (ELPs; [VPGVG]3) at different molar ratios, were simulated. Simulations were carried out for 2 μs using the coarse-grained (CG) model that had captured the experimentally observed phase behavior of PEGylated lipids and lateral diffusivity of DPPC bilayers. Starting with the initial position of ELPs on the bilayer surface, ELPs insert into the hydrophobic region of the bilayer because of their interaction with lipid tails, consistent with previous all-atom simulations. Lateral diffusion coefficients of DPPCs significantly increase in the bilayer composed of more ELPs and less cholesterols, showing their opposite effects on the bilayer dynamics. In particular, ELPs modulate the dynamics and phase for the disordered liquid bilayer, but not for the ordered gel bilayer, indicating that ELPs can destabilize only the disordered bilayer. In the ordered bilayer, ELP chains tend to have a spherical shape and slowly diffuse, while they are extended and diffuse faster in the disordered bilayer, indicating the effect of the bilayer phase on the conformation and diffusivity of ELPs. These findings explain the experimental observation that the ELP-conjugated liposomes are stable at 310 K (ordered phase) but become unstable and release the encapsulated drugs at 315 K (disordered phase), which suggests the effects of ELPs and cholesterols. Since the cholesterol-stabilized bilayer can be destabilized by the extended shaped ELPs only in the disordered phase (not in the ordered phase), the inclusion of cholesterols is required to safely shield drugs at 310 K as well as allow ELPs to disrupt lipids and destabilize the liposomes at 315 K.
    Physical Chemistry Chemical Physics 01/2014; 16(8). DOI:10.1039/c3cp52639a · 4.20 Impact Factor
  • Eol Han, Hwankyu Lee
    Biophysical Journal 01/2014; 106(2):98a-99a. DOI:10.1016/j.bpj.2013.11.615 · 3.83 Impact Factor
  • Hwankyu Lee
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    ABSTRACT: Single-walled carbon nanotubes (SWNTs) covalently or noncovalently modified with polyethylene glycol (PEG) of different sizes (Mw = 550, 2000, 5000, and 7000) and grafting densities (5–16 PEGs per SWNT) were simulated using coarse-grained force fields. The covalently grafted PEGs are evenly distributed on SWNTs, while the noncovalently PEGylated SWNTs show the random distribution of PEGylated lipids adsorbed to the SWNT, in which the SWNT sidewall is less completely wrapped by PEGs and thus largely exposed to water, as was observed in experiments. For covalently PEGylated SWNTs, longer PEG chains with higher grafting density yield a larger size, more isotropic shape, and lower diffusivity of the SWNT–PEG complex. In particular, at low grafting density, the thickness of the PEG layer on SWNTs nearly equals the size of the mushroom, where the end-to-end distance of PEGs is smaller than the distance between the grafting points, similar to the conformation of an isolated chain in water. However, at high grafting density, the thickness of the PEG layer increases beyond the mushroom regime, indicating a mushroom-to-brush transition, in agreement with the Alexander–de Gennes theory. These findings indicate that the PEGylation method influences the distribution of PEG chains on SWNTs and that the PEG size and grafting density modulate the conformation of the conjugated PEG chains, which helps explain the experimentally proposed transition of the PEG conformation between mushroom and brush.
    The Journal of Physical Chemistry C 11/2013; 117(49):26334–26341. DOI:10.1021/jp4093749 · 4.84 Impact Factor
  • Eol Han, Hwankyu Lee
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    ABSTRACT: Bax-α5 and Bcl-xL-α5, which are shorter versions of apoptosis-regulating proteins Bax and Bcl-xL, were simulated with lipid bilayers composed of pure dioleoylglycerophosphocholine (DOPC) lipids or a mixture of DOPCs and cholesterols. Starting with the initial peptide position near the bilayer surface, both Bax-α5 and Bcl-xL-α5 bind to the bilayer because of their charge interactions with lipid head groups. After binding to the bilayer surface, Bax-α5 inserts into the pure DOPC bilayer, but not into the DOPC-cholesterol bilayer, showing the effect of cholesterols on the peptide-bilayer interaction. Despite the similar peptide structure, Bcl-xL-α5 does not insert into the bilayer, in contrast to the interaction of Bax-α5 with the bilayer. Bcl-xL-α5 predominantly has the random-coil structure in both aqueous and membrane environments, while Bax-α5 shows a higher extent of α-helical structure in the bilayer than in water, in quantitative agreement with experiment. In particular, although Bax-α5 and Bcl-xL-α5 have the same extent of the electrostatic interaction with lipid head groups, Bax-α5 has stronger hydrophobic interaction with lipid tails than does Bcl-xL-α5. These indicate that Bax-α5 retains α-helical structure, where hydrophobic residues on one side of the α-helix interact with lipid tails and thus can easily attract the peptide into the lipid-tail region, while Bcl-xL-α5 forms a random coil that tends to spread on the bilayer surface and thus has weaker hydrophobic interaction with lipid tails. Our findings help explain the experimental observation that showed that Bax-α5 disorders lipids and induces pore formation, but Bcl-xL-α5 does not.
    Physical Chemistry Chemical Physics 11/2013; 16(3). DOI:10.1039/c3cp53486c · 4.20 Impact Factor
  • Eol Han, Hwankyu Lee
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    ABSTRACT: Polyethylene glycol (PEG)-grafted magainin 2 and tachyplesin I were simulated with lipid bilayers. In the simulations of PEGylated magainin 2 and tachyplesin I in water, both peptides are wrapped by PEG chains. The α-helical structure of PEGylated magainin 2 is broken in water, while β-sheet of PEGylated tachyplesin I keeps stable, similar to the structural behavior of unPEGylated peptides, in agreement with experiments. Simulations of PEGylated peptides with lipid bilayers show that PEG chains block the electrostatic interaction between cationic residues of peptides and anionic phosphates of lipids, leading to the less binding of the peptide to the bilayer surface, which is observed more significantly for magainin 2 than for tachyplesin I. Since the random-coiled magainin 2 can be more completely covered by PEGs than does the β-sheet tachyplesin I, the PEGylation effect on the decreased binding is larger for magainin 2, showing the dependence of PEGylation on the peptide structure. These simulation findings qualitatively support the experimental observation of the different extents of the reduced membrane-permeabilizing activity for PEGylated magainin 2 and tachyplesin I.
    Langmuir 10/2013; 29(46). DOI:10.1021/la4036985 · 4.38 Impact Factor
  • Hwankyu Lee
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    ABSTRACT: We performed coarse-grained (CG) molecular dynamics (MD) simulations of single-walled carbon nanotubes (SWNTs) with lipid bilayers to understand the effect of the SWNT diameter, length, and concentration on membrane curvature and penetration. Starting with different orientations of multiple SWNTs near lipid bilayers, simulations show that SWNTs insert into the bilayer and induce membrane curvature, which is much larger than that observed from previous simulations of a single SWNT. Longer and thicker SWNTs at higher concentration cause larger membrane curvature, indicating the effect of the SWNT size and concentration, in qualitative agreement with experiments. In particular, thicker SWNTs significantly increase the bilayer height and the difference of the projected and contour bilayer areas, decrease the area compressibility, and disorder lipids. When inserted into the bilayer, thinner SWNTs mainly contact the entire tails of lipids, while thicker SWNTs are wrapped mainly by the ending tail-carbons, leading to the larger membrane curvature. This indicates the effect of SWNT diameter on the SWNT-lipid interaction, yielding different extents of membrane curvature. These findings imply that the SWNT-induced membrane penetration and curvature are modulated by a combination of SWNT length, diameter, and concentration.
    Physical Chemistry Chemical Physics 09/2013; 15(38). DOI:10.1039/c3cp52747f · 4.20 Impact Factor
  • Sangwoo Park, Hwankyu Lee, Sang-Yup Lee
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    ABSTRACT: The conformational effects of lysine-rich peptides on the biomineralization of TiO2 were investigated. The biomineralization activity of the peptide was dependent on the spatial proximity of the amino groups, which is determined by the secondary structure.
    Dalton Transactions 08/2013; 42(38). DOI:10.1039/c3dt51040a · 4.10 Impact Factor
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    ABSTRACT: Heparin decomplexation experiments, as well as all-atom (AA) and coarse-grained (CG) molecular dynamics (MD) simulations were performed to determine the effect of the size of arginine(Arg)-rich peptides on the structure and binding strength of the siRNA-peptide complex. At a fixed peptide/siRNA mole ratio of 5:1 or 10:1, the siRNA complexes with peptides longer than 9 Arg residues are more easily decomplexed by heparin than are those with 9 Arg residues. At these mole ratios, peptides longer than 9 Arg residues have cationic/anionic charge ratios in excess of unity, and produce more weakly bound complexes than 9-Arg residue ones do. AA simulations of mixtures of peptides with a single siRNA show formation of an electrostatically-induced complex, and the longer peptides produce a larger complex, but with no significant increase in the number of Arg residues bound to the siRNA. Larger-scale CG-MD simulations show that multiple siRNAs can be linked together by peptides into a large complex, as observed in the experiments. The peptides longer than 9 residues, which at mole ratio 5:1 yield a peptide/siRNA charge ratio in excess of unity, include many non-interacting Arg residues, which repel each other electrostatically. This leads to a less dense complex than for 9-residue peptides, which can explain why these longer complexes are more easily decomplexed by heparin molecules, as observed in the experiments. The key role of the charge ratio is supported by simulations that show that at a mole ratio of 2.5 peptides per siRNA, the longer 18-residue peptide has a charge ratio of roughly unity, and also shows a tight complex, just as the 9-residue peptide does at a 5:1 mole ratio, where its charge ratio is also unity.
    The Journal of Physical Chemistry B 05/2013; 117(23). DOI:10.1021/jp402868g · 3.38 Impact Factor
  • Hwankyu Lee
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    ABSTRACT: Single-walled carbon nanotubes (SWNTs) wrapped with different types of lipids and polyethylene glycol (PEG)-grafted lipids were simulated with lipid bilayers. Simulations were carried out with the previously parametrized coarse-grained (CG) SWNT and PEG force fields that had captured the experimentally observed conformations of self-assembled SWNT-lipid complexes and phase behavior of PEG-grafted lipids. Simulations of multiple copies of the SWNT in water show that all pure SWNTs aggregate, lipid-wrapped SWNTs partially aggregate, but those wrapped with lipids grafted to PEG (Mw=550) completely disperse, indicating the effect of short PEG chains on interparticle aggregation, in agreement with experiment. Starting with initial SWNT orientation parallel to the bilayer surface, SWNTs wrapped with lysophospholipids and PEG(Mw=550)-grafted lipids insert into the hydrophobic region of the bilayer, while SWNTs wrapped with phospholipids and longer PEG(Mw=2000)-grafted lipids do not. These indicate that SWNTs insert because of the hydrophobic interaction with the bilayer tails, but the tight wrapping of charged lipid headgroups and long hydrophilic PEG chains can weaken the hydrophobic interaction and inhibit SWNT insertion. The inserted SWNT contact the entire tails of neighboring lipids in one leaflet of the bilayer, which disorders the lipid bilayer and induces positive curvature. Our findings indicate that interparticle aggregation, SWNT penetration, and membrane curvature can be modulated by the SWNT-lipid structure and the PEG length.
    The Journal of Physical Chemistry B 12/2012; 117(5). DOI:10.1021/jp308912r · 3.38 Impact Factor
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    ABSTRACT: We performed all-atom and coarse-grained (CG) molecular dynamics (MD) simulations of lipid bilayers grafted with elastin-like polypeptides (ELPs; [VPGVG]n). All-atom simulations of a single ELP in water show that ELPs become more collapsed and folded as the temperature increases from 293 up to 353 K, in agreement with experiments. All-atom simulations of lipid bilayers composed of dipalmitoylglycerophosphocholine (DPPC), cholesterol, and fatty acids grafted with ELPs show that ELPs insert into the bilayer and significantly disorder lipids, to an extent that depends on the ELP length over the temperature range 293–323 K. In the bilayer, ELPs are mainly, but not entirely, random coil in character at temperatures between 293 and 315 K and, in contrast to the behavior in water, become increasing random coil and extended in length over the range 315–323 K, over which the bilayer is in the disordered liquid phase. The insertion of ELPs into the lipid-tail region is mediated by the interaction of hydrophobic Pro and Val residues with lipid tails, which become stronger at increased temperature, but the insertion is incomplete because of the interaction between hydrophilic backbones of Gly residues and the lipid headgroups. Longer time CG simulations of the transition from ordered gel to disordered liquid bilayer at 315 K in a liposome are able to capture cholesterol flip-flops between bilayer leaflets, leading to an increase in the number of cholesterols in the inner layer, which helps the bilayer accommodate the reduced membrane curvature resulting from the expansion of the bilayer area driven by the phase transition. Our findings indicate that lipid bilayers can be disrupted more effectively by the stronger hydrophobic interaction of the random coils of ELPs at 315–323 K than by the compact ELPs at 293–310 K, which helps explain the experimental observation that ELP-conjugated liposomes are stable at 310 K, but become unstable and release drugs at 315 K.
    Macromolecules 09/2012; 45(17):7304-7312. DOI:10.1021/ma301327j · 5.93 Impact Factor
  • Hwankyu Lee
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    ABSTRACT: G4 and G5 polyamidoamine dendrimers solvated with explicit water, counterions and NaCl ions (0.15, 1 M) were simulated at two levels of protonation, which mimic their electrostatic charges at pH 5 and 7. We used the previously parametrised coarse-grained dendrimer model which had predicted the experimentally measured and theoretically calculated size and internal structure of the dendrimer at different pH values. In this study, addition of ≤ 1 M NaCl does not significantly modulate the dendrimer size, in agreement with experiments and other theoretical studies. In particular, added salt ions do not change the dense-shell and dense-core structures of dendrimers without salt, respectively, at pH 5 and 7. Besides counterions, only a few excess ions penetrate and occupy the dendrimer interior, leading to unchanged volume of the inner cavity in the dendrimer core. These results indicate that addition of ≤ 1 M NaCl does not modulate the efficiency of encapsulating hydrophobic drugs or compounds.
    Molecular Simulation 06/2012; DOI:10.1080/08927022.2011.652629 · 1.12 Impact Factor

Publication Stats

1k Citations
167.26 Total Impact Points

Institutions

  • 2011–2014
    • Dankook University
      • Department of Chemical Engineering
      Eidō, Chungcheongbuk-do, South Korea
  • 2008–2011
    • National Heart, Lung, and Blood Institute
      베서스다, Maryland, United States
    • University of Michigan
      Ann Arbor, Michigan, United States
  • 2008–2009
    • National Institutes of Health
      • Laboratory of Cell Biology
      Maryland, United States