Interaction Of Monomers Research Articles

Computational design of dummy molecularly imprinted polymers via hydrogen bonding investigation for oxytetracycline determination

Oxytetracycline (OTC), a banned broad-spectrum antibiotic, currently requires highly selective and specific determination methods to measure its concentration below 200 ppb in foods of animal origin. Molecular imprinting technology could be utilized to construct a highly selective and cost-effective synthetic receptor for OTC. In this work, we investigated different monomers in designing a dummy MIP for OTC detection using TC as the dummy template. Template-monomer complexes of pre-polymerization mixtures were modeled using density functional theory for geometry optimization, intermolecular hydrogen-bonding situation, and interaction energies. O-phenylenediamine (OPD) at TC:OPD molar ratio = 1:7 was shown to be the optimum monomer, forming 11 stable intermolecular hydrogen bonds with TC and having the lowest interaction energy among the complexes. We also presented indole, pyrrole, and carbazole to be plausible monomers for imprinting TC; however, they are energetically less-favored than OPD. This study provides aid in dummy MIP design for OTC concentration measurement using the molecular level interaction of different monomers with the template TC.

Biological effects of resin monomers on oral cell populations: descriptive analysis of literature.

Recently, the application of restorative materials containing metacrilate monomers in the conservative and paediatric dentistry has focused on the possible negative effects due to the use of these composites. In particular the release of monomers from reconstructions as a result of an insufficient polymerisation, can spread along the mucosal and dental tissues with potential immunological ed cytotoxic effects. Regarding to the importance of this issue, the aim of this study is to provide a descriptive review of the literature on potential local and systemic interactions of metacrylic and acrylic monomers with the immune system, both in vitro and in vivo. The most highly used monomers in composite materials applied in conservative dentistry include: 2-hydroessietil- methacrylate (HEMA), triethylene glycol-dimethacrylate (TEGDMA), bisphenol A glycidyl-methacrylate (BisGMA) and urethane- dimethacrylate (UDMA). Different investigations have been performed for better understanding of the potential side effects of metacrylic monomers on immune system cells. Different factors such as cell population, exposure time and parameters more strictly connected to these materials, such as molecular weight, chemical composition and mechanical characteristics, seem to be directly involved in these reactions.

Design and prediction of dye dispersibility stabilized by polymeric dispersants using a Dye–Monomer interaction force measurement

In this study, we propose a dye–monomer interaction force measurement technique based on atomic force microscopy (AFM) to predict the performance of polymeric dispersants. Cantilevers modified with functional monomers such as styrene, N-butyl acrylate (BA), and 2-(N-phthalimido)ethyl methacrylate (PEMA) were used to characterize the interaction force between these functional monomers and a target dye (Disperse Blue 359). The interaction forces of each monomer—styrene, BA, and PEMA—with Disperse Blue 359 were measured as 10.75 nN, 7.06 nN, and 21.31 nN, respectively, and their trend was consistent with dipole-moment values obtained from density function theory (DFT) calculations (μ(styrene) = 0.0001, μ(PEMA) = 2.3158, μ(Disperse Blue 359) = 3.0368). We synthesized a series of model polymers containing specific functional monomers (CoPS10, CoBA, CoPPEMAs) with similar molecular weights, molecular-weight distributions, and acid contents and compared their actual performance with that predicted from interaction force measurement data. The results were well correlated with the interaction force measurement data. The effect of the PEMA content on dye dispersion stability was also investigated; the results indicated that both the PEMA content and the type of dye-interacting group greatly influenced the characteristics of the dispersion.

Inhibition of the Self-Assembly of Aβ and of Tau by Polyphenols: Mechanistic Studies.

The amyloid-β (Aβ) peptide and tau protein are thought to play key neuropathogenic roles in Alzheimer’s disease (AD). Both Aβ and tau self-assemble to form the two major pathological hallmarks of AD: amyloid plaques and neurofibrillary tangles, respectively. In this review, we show that naturally occurring polyphenols abundant in fruits, vegetables, red wine, and tea possess the ability to target pathways associated with the formation of assemblies of Aβ and tau. Polyphenols modulate the enzymatic processing of the amyloid-β precursor protein and inhibit toxic Aβ oligomerization by enhancing the clearance of Aβ42 monomer, modulating monomer–monomer interactions and remodeling oligomers to non-toxic forms. Additionally, polyphenols modulate tau hyperphosphorylation and inhibit tau β-sheet formation. The anti-Aβ-self-assembly and anti-tau-self-assembly effects of polyphenols increase their potential as preventive or therapeutic agents against AD, a complex disease that involves many pathological mechanisms.

Loops in Polymer Networks

The classical theory suggests that phantom polymer networks have a treelike structure. In this study, we investigate the actual polymer networks, in which the polymer loops have a finite size and strongly overlap with each other. We show that the elastic modulus of such networks has two contributions: of elastically effective strands and of finite size loops shunting the network strands. The latter contribution substantially depends on the interaction of the network strand monomers at network preparation conditions. The result of calculations performed in the framework of the replica theory of polymer networks is interpreted using a generalized combined chain model. This model allows us to describe quantitatively the elasticity of the polymer network with finite size loops and the deformation of its individual strands. We also calculate the impact of primary loops and cyclic defects of arbitrary concentration on the elasticity of such a network.

Tensile Strength of Porous Dust Aggregates

Abstract Comets are thought to have information about the formation process of our solar system. Recently, detailed information about comet 67P/Churyumov–Gerasimenko was found by Rosetta. It is remarkable that its tensile strength was estimated. In this paper, we measure and formulate the tensile strength of porous dust aggregates using numerical simulations, motivated by a porous dust aggregation model of planetesimal formation. We perform three-dimensional numerical simulations using a monomer interaction model with a periodic boundary condition. We stretch out a dust aggregate with a various initial volume filling factor between 10−2 and 0.5. We find that the tensile stress takes the maximum value at the time when the volume filling factor decreases to about half of the initial value. The maximum stress is defined to be the tensile strength. We take an average of the results with 10 different initial shapes to smooth out the effects of initial shapes of aggregates. Finally, we numerically obtain the relation between the tensile strength and the initial volume filling factor of dust aggregates. We also use a simple semi-analytical model and successfully reproduce the numerical results, which enables us to apply a wide parameter range and different materials. The obtained relation is consistent with previous experiments and numerical simulations about silicate dust aggregates. We estimate that the monomer radius of comet 67P has to be about 3.3–220 μm to reproduce its tensile strength using our model.

NMR spectroscopy for assessing cocaine-functional monomer interactions when preparing molecularly imprinted polymers

Synthesis of molecularly imprinted polymers (MIPs) implies a previous pre-polymerization stage in which the template (the molecule for which the MIP offers the specific recognition cavities) interacts with the adequate functional monomer, just before the addition of the cross-linker and the initiator for performing the polymerization synthesis. The recognition properties, as well as the physical properties of the prepared MIP beads, are dependent on the successful template-monomer interaction during the pre-polymerization stage. Investigations by proton nuclear magnetic resonance (1H NMR) and nuclear overhauser effect (NOE) were performed to study the interactions between the template (cocaine) and the monomers (methacrylic acid and ethylene dimethacrylate). Experimental results were additionally compared to those obtained by in silico studies.

Interaction of Caffeic Acid with SDS Micellar Aggregates.

Micellar systems consisting of a surfactant and an additive such as an organic salt or an acid usually self-organize as a series of worm-like micelles that ultimately form a micellar network. The nature of the additive influences micellar structure and properties such as aggregate lifetime. For ionic surfactants such as sodium dodecyl sulfate (SDS), CMC decreases with increasing temperature to a minimum in the low-temperature region beyond which it exhibits the opposite trend. The presence of additives in a surfactant micellar system also modifies monomer interactions in aggregates, thereby altering CMC and conductance. Because the standard deviation of β was always lower than 10%, its slight decrease with increasing temperature was not significant. However, the absolute value of Gibbs free enthalpy, a thermodynamic potential that can be used to calculate the maximum of reversible work, increased with increasing temperature and caffeic acid concentration. Micellization in the presence of caffeic acid was an endothermic process, which was entropically controlled. The enthalpy and enthropy positive values resulted from melting of “icebergs” or “flickering clusters” around the surfactant, leading to increased packing of hydrocarbon chains within the micellar core in a non-random manner. This can be possibly explained by caffeic acid governing the 3D matrix structure of water around the micellar aggregates. The fact that both enthalpy and entropy were positive testifies to the importance of hydrophobic interactions as a major driving force for micellization. Micellar systems allow the service life of some products to be extended without the need to increase the amounts of post-harvest storage preservatives used. If a surfactant is not an allowed ingredient or food additive, carefully washing it off before the product is consumed can avoid any associated risks. In this work, we examined the influence of temperature and SDS concentration on the properties of SDS–caffeic acid micellar systems. Micellar properties can be modified with various additives to develop new uses for micelles. This allows smaller amounts of additives to be used without detracting from their benefits.

Spectral-fluorescent study of the interaction of polymethine dye probes with biological surfactants - bile salts.

Spectral-fluorescent properties of polymethine dye probes anionic 3,3'-di(sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine-betaine (DEC) and cationic 3,3',9-trimethylthiacarbocyanine iodide (Cyan 2) in the presence of biological surfactants, bile salts sodium cholate (NaC), sodium deoxycholate (NaDC) and sodium taurocholate (NaTC), as well as sodium dodecyl sulfate (SDS), have been studied in a wide range of surfactant concentrations. When a surfactant is introduced into a solution of DEC, changes of the spectral-fluorescent properties are observed due to decomposition of dye dimers into cis-monomers and cis-trans conversion of the resulting monomers. In the presence of SDS, both processes occur in parallel, caused by noncovalent interaction of dye monomers with micelles, and mainly occur near the critical micelle concentration (CMC). In contrast, upon the introduction of increasing concentrations of bile salts, decomposition of dye dimers into the monomers begins at lower concentrations than cis-trans conversion. The former process is almost completed at concentrations close to CMC of secondary micelles (CMC2), while the latter process occurs even at concentrations of bile salts much higher than CMC2. Hence, DEC can serve as a probe that permits estimating the value of CMC2 and is indicative of reorganization of secondary micelles upon an increase in bile salt concentration. Aggregation of DEC and Cyan 2 on bile salts is also observed. Since it is observed at relatively low concentrations of bile salts (<CMC2), the aggregation probably occurs on monomeric molecules of bile salts and their small associates and primary micelles. Decomposition of the aggregates formed begins at concentrations of bile salts above CMC2 (that is, upon the interaction with secondary micelles).

Stress in a polymer brush

We study the stress distribution in a polymer brush material over a range of graft densities, using theory and molecular dynamics (MD) simulations. MD simulations confirmed the quartic variation of the normal stress within the bulk of the brush, as predicted in our previous work. However, in the high graft density regime, further improvements to the theory are needed, as it is known that finite extensibility effects (force-extension divergence) invalidate Gaussian elasticity of chains, and the restriction to binary interaction among monomers is insufficient. This motivated us to extend a semi-analytical strong stretching theory (SST) for polymer brushes that use Langevin force-extension relation for chains and a modified Carnahan–Starling (CS) equation of state to model monomer interactions. Our extended theory elucidates the stress profiles obtained from MD simulations. It reproduces Gaussian chain results for small graft densities, and shows a good qualitative agreement with MD results for monomer density profile, end density profile and stress profile for high graft densities without the need for fitting parameters (virial coefficients). Quantitative comparisons of MD results with various available theories suggest that excluded volume correlations may be important.

Novel Phosphonium Dye TDV1 as a Potential Fluorescent Probe to Monitor DNA Interactions with Lysozyme Amyloid Fibrils

The applicability of the novel cationic phosphonium dye TDV1 to monitor the complexation between DNA and pathologically aggregated proteins, amyloid fibrils, was tested using the optical spectroscopy and molecular docking techniques. TDV1 has been found to be highly emissive in buffer solution and is characterized by one well-defined fluorescence peak attributed to the dye monomers. The association of the dye with the double stranded DNA was followed by the enhancement of monomer fluorescence coupled with a bathochromic shift of the emission maximum. The addition of fibrillar lysozyme (LzF) to TDV1-DNA mixture led to the further enhancement of fluorescence intensity of the monomeric dye form coupled with a hypsochromic shift of the emission maximum and an appearance of a second long-wavelength peak. An assumption has been made that the fluorescence enhancement augmenting with increasing the protein concentration in the TDV1/DNA system is produced by the interaction of the free TDV1 monomers with lysozyme fibrils as well as by the LzF-induced conformational alterations of DNA. The long-wavelength peak emerging in the presence of LzF is presumably a consequence of the J-aggregate formation upon the TDV1 association with lysozyme fibrils. The molecular docking studies showed that TDV1 monomers are incorporated into the fibril grooves associating with 7 β-strands in such a way that the dye long axis is parallel to the fibril axis. The most energetically favorable position of TDV1 is the S60-W62/G54-L56 groove in the lysozyme fibril core. In contrast, the TDV1 dimers seem to associate with the more hydrophilic side of the model β-sheet. Cumulatively, the results from the absorption and fluorescence measurements, together with the molecular docking analysis are consistent with the minor groove mode of the TDV1 binding to dsDNA. The electrostatic interactions seem to play a predominant role in the TDV1 complexation with the double stranded DNA, while the hydrophobic interactions and steric hindrances are supposed to be influential in the association of TDV1 with fibrillar lysozyme.

Monte Carlo simulation of coil-to-globule transition of compact polymer chains: Role of monomer interacting

Coil-to-globule transitions are fundamental problems existing in polymer science for several decades; however, some features are still unclear, such as the effect of chain monomer interaction. Herein, we use Monte Carlo simulation to study the coil-to-globule transition of simple compact polymer chains. We first consider the finite-size effects for a given monomer interaction, where the short chain exhibits a one-step collapse while long chains demonstrate a two-step collapse, indicated by the specific heat. More interestingly, with the decrease of chain monomer interaction, the critical temperatures marked by the peaks of heat capacity shift to low values. A closer examination from the energy, mean-squared radius of gyration and shape factor also suggests the lower temperature of coil-to-globule transition.

Net nitrogen mineralization and enzyme activities in an alpine meadow soil amended with litter tannins

AbstractCondensed tannins in plant litter play an important role in soil nitrogen (N) cycling at the plant–soil interface. However, how soil net N mineralization is affected by litter tannins through their interactions with soil enzymes remains unclear. The aims of our study are to explore the effects of litter tannins with different structures on soil net N mineralization and on the activities of soil enzymes that are directly or indirectly related to N mineralization. Soils were collected from a Tibetan alpine meadow community dominated by a tannin‐rich forb species, Polygonum viviparum. Condensed tannins purified from the litter were separated into the light‐fraction and heavy‐fraction tannins, with the former having a lower mean degree of polymerization and a higher prodelphinidin:procyanidin (PD:PC) monomer ratio in the structure than the latter. Soils were amended with the light‐fraction, heavy‐fraction, and unfractionated tannins, and then incubated for four weeks. The dynamics of soil enzyme activities and soil net N mineralization were monitored during the incubation. The results show that among the enzyme activities tested, the activities of laccase and peroxidase were significantly inhibited by the three tannins, whereas the activity of polyphenol oxidase was only significantly suppressed by the heavy‐fraction tannins. The overall activity of urease was not significantly affected by the tannin additions. In contrast, the activity of N‐acetyl‐β‐D‐glucosaminidase was significantly enhanced by the three tannins. These results suggest that the interactions between litter tannins and soil enzymes rely on both the structure of the tannins and the type of enzymes. Soil net N mineralization was significantly decreased by the three tannins, which could be attributed to the decreased net ammonification and increased immobilization of inorganic N. The light‐fraction tannins caused a more pronounced inhibitory effect on soil net N mineralization than the heavy‐fraction and unfractionated tannins, probably due to the stronger interaction of the PD monomers with soil enzymes and soil organic N compounds than the PC monomers. Overall, this study indicates that litter tannins with different structures could exert different effects on the activities of soil enzymes as well as on soil net N mineralization, which is important for interpreting the role of different litter tannins in N cycling at the plant–soil interface.

Polymerization driven monomer passage through monolayer chemical vapour deposition graphene

Mass transport through graphene is receiving increasing attention due to the potential for molecular sieving. Experimental studies are mostly limited to the translocation of protons, ions, and water molecules, and results for larger molecules through graphene are rare. Here, we perform controlled radical polymerization with surface-anchored self-assembled initiator monolayer in a monomer solution with single-layer graphene separating the initiator from the monomer. We demonstrate that neutral monomers are able to pass through the graphene (via native defects) and increase the graphene defects ratio (Raman ID/IG) from ca. 0.09 to 0.22. The translocations of anionic and cationic monomers through graphene are significantly slower due to chemical interactions of monomers with the graphene defects. Interestingly, if micropatterned initiator-monolayers are used, the translocations of anionic monomers apparently cut the graphene sheet into congruent microscopic structures. The varied interactions between monomers and graphene defects are further investigated by quantum molecular dynamics simulations.

NMR Investigations of the Catalyst–Monomer Interaction and Stereochemistry of the Product in Catalytic Polymerization of 2-Hydroxyethyl Methacrylate

Nuclear magnetic resonance (NMR) spectroscopy has been used to study the structure of the product and possible intermediates in the polymerization of 2-hydroxyethyl methacrylate catalyzed by the oxovanadium (IV) complex. The assumption of the coordination nature of the polymerization is confirmed by noncovalent interactions between monomer and the catalyst, which has been examined by NMR on 1H, 13C, and 17O nuclei. The catalyst affects remarkably the stereospecificity of the reaction. The resulting polymer with high molecular weight Mn ≈ 200,000 has a predominantly syndiotactic structure; the chain growth is satisfactorily described by the first-order Markov model with the statistical parameters Pr/m = 0.156 and Pm/r = 0.857.

Smear Layer-Deproteinization: Improving the Adhesion of Self-Etch Adhesive Systems to Caries-Affected Dentin

This paper reviews a new method of dentin surface modification, smear layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected dentin. Remnants of smear debris, which forms hybridized smear layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying dentin. The hybridized smear layer weakens the physical and chemical properties of the resin-dentin hybridized complex both immediately and over time. Smear layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-dentin interface of self-etch adhesives through elimination of the hybridized smear layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the dentin surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the dentin surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem. Smear layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected dentin than normal dentin because caries-affected dentin produces a thicker organic-rich smear layer. Smear layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.

Atomistic Modeling of F-Actin Mechanical Responses and Determination of Mechanical Properties.

A molecular structural mechanics (MSM) model was developed for F-actins in cells, where the force constants describing the monomer interaction were achieved using molecular dynamics simulations. The MSM was then employed to predict the mechanical properties of F-actin. The obtained Young's modulus (1.92 GPa), torsional rigidity (2.36 × 10-26 Nm2), and flexural rigidity (10.84 × 10-26 Nm2) were found to be in good agreement with existing experimental data. Subsequently, the tension-induced bending was studied for F-actins as a result of their helical structure. Mechanical instability was also investigated for the actin filaments in filopodial protrusion by considering the reinforcing effect of the actin-binding proteins. The predicted buckling load agreed well with the experimentally obtained stall force, showing a pivotal role of the actin-binding protein in regulating the stiffness of F-actin bundles during the formation of filopodia protrusion. Herein, it is expected that the MSM model can be extended to the mechanics of more complex filamentous systems such as stress fibers and actin meshwork.

Interaction of Zwitterionic and Ionic Monomers with Graphene Surfaces.

Measurement of the interaction force between two materials provides important information on various properties, such as adsorption, binding, or compatibility for coatings, adhesion, and composites. The interaction forces of zwitterionic and ionic monomers with graphite platelets (G) and reduced graphene oxide (rGO) surfaces were systematically investigated by atomic force microscopy (AFM) in air and water. The monomers examined were 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBE), [2-(acryloyloxy)ethyl]trimethylammonium chloride (ATC), and 2-methyl-2-propene-1-sulfonic acid sodium (MSS). The AFM studies revealed that MSS and SBE monomers with sulfonate units have stronger interaction forces with G surface in air and that MPC and ATC monomers with quaternary ammonium units have higher interaction forces in water. In the case of rGO surface, the monomers with quaternary ammonium units showed stronger interactions regardless of the medium. These interactions could be rationalized by the interaction mechanism between the monomers with graphene surfaces, such as cation-π for MPC and ATC and anion-π for MSS and SBE. Overall, cation-π interactions were effective in water, whereas anion-π interactions are effective in air with G surface. The adhesion values of MPC, SBE, ATC, and MSS on rGO were lower than the values measured on G surface. Among the monomers, MPC showed the highest dispersibility for aqueous graphene dispersions. Further, the adsorption of MPC on G and rGO surfaces was verified by high-resolution transmission electron microscopy and X-ray diffraction patterns.

Mechanistic Study on Water Splitting Reactions by Small Silicon Clusters Si3X, X = Si, Be, Mg, Ca.

Interaction, dissociation, and dehydrogenation reactions of water monomer and dimer with pure and mixed tetrameric silicon clusters Si3X with X = Si, Be, Mg, Ca were investigated using high accuracy quantum chemical calculations. While geometries were optimized using the DFT/B3LYP functional with the aug-cc-pVTZ basis set, reaction energy profiles were constructed making use of the coupled-cluster theory with extrapolation to complete basis set, CCSD(T)/CBS. Cleavage of the O-H bond in water dimer is found to be more favored than that of water monomer in the reaction with Si4. The water acceptor monomer in water dimer performs as an internal catalyst facilitating H atom transfer to form H2. Adsorption of water dimer on Si3X clusters mostly takes place upon interaction of the donor water molecule with Si cluster. Water dimer adsorbs more strongly on Si3M than on Si4. The most stable complexes obtained upon interaction of water dimer with Si3M mainly arise from M-O interaction in preference over a Si-O connection. Substitution of a Si atom in Si4 by an earth alkaline metal induces a substantial reduction of the energy barrier for the (rate-limiting) first O-H bond cleavage of water dimer. The most remarkable achievement upon doping is a disappearance of the overall energy barrier for the initial O-H bond cleavage in water dimer. Of the three binary Si3M clusters considered, dehydrogenation of water dimer driven by Si3Be is the most kinetically and thermodynamically favorable pathway. In comparison to another cluster such as Al6 and nanoparticles Ru55, energy barriers for water dimer dissociation on Si3M are much lower. The mixed clusters Si3M turn out to be as efficient alternative reagents for O-H dissociation and hydrogen production from water dimer. This study proposes further searches for other mixed silicon clusters as realistic gas phase reagents for crucial dehydrogenation processes in such a way they can be prepared and conducted in experiment.

Interaction of monomeric Ebola VP40 protein with a plasma membrane: A coarse-grained molecular dynamics (CGMD) simulation study

Ebola virus is a lipid-enveloped filamentous virus that affects human and non-human primates and consists of several types of protein: nucleoprotein, VP30, VP35, L protein, VP40, VP24, and transmembrane glycoprotein. Among the Ebola virus proteins, its matrix protein VP40 is abundantly expressed during infection and plays a number of critical roles in oligomerization, budding and egress from the host cell. VP40 exists predominantly as a monomer at the inner leaflet of the plasma membrane, and has been suggested to interact with negatively charged lipids such as phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylserine (PS) via its cationic patch. The hydrophobic loop at the C-terminal domain has also been shown to be important in the interaction between the VP40 and the membrane. However, details of the molecular mechanisms underpinning their interactions are not fully understood. This study aimed at investigating the effects of mutation in the cationic patch and hydrophobic loop on the interaction between the VP40 monomer and the plasma membrane using coarse-grained molecular dynamics simulation (CGMD). Our simulations revealed that the interaction between VP40 and the plasma membrane is mediated by the cationic patch residues. This led to the clustering of PIP2 around the protein in the inner leaflet as a result of interactions between some cationic residues including R52, K127, K221, K224, K225, K256, K270, K274, K275 and K279 and PIP2 lipids via electrostatic interactions. Mutation of the cationic patch or hydrophobic loop amino acids caused the protein to bind at the inner leaflet of the plasma membrane in a different orientation, where no significant clustering of PIP2 was observed around the mutated protein. This study provides basic understanding of the interaction of the VP40 monomer and its mutants with the plasma membrane.