Phospholipid Membrane Interactions of Model Ac-WL-X-LL-OH Peptides Investigated by Solid-State Nuclear Magnetic Resonance.

The role of aromatic amino acids in peripheral protein membrane binding has been reported to involve cation-π interactions with choline lipids. In this study, we have investigated the interactions of the model pentapeptide Ac-WL-X-LL-OH (where X = L, Y, F, or W) with the phospholipid membrane using solid-state NMR. The effect of guest residue X on the peptide-lipid interactome was complementary to the seminal report on the interfacial hydrophobicity scale by Wimley and White.

Investigating mobility of crude oil adsorbates on mineral surfaces by NMR.

We have applied diffusion and relaxation Nuclear Magnetic Resonance experiments to investigate the translational and rotational mobility of adsorbents on quartz and calcite mineral surfaces. On both surfaces it was found that water is the dominant molecule. On the quartz surface the majority of water molecules have a relatively high degree of both rotational and translational mobility, while a minor fraction of water molecules, and all hydrocarbon molecules, have a significantly lower mobility.

Effects and Location of Coplanar and Noncoplanar PCB in a Lipid Bilayer: A Solid-State NMR Study.

Coplanar and noncoplanar polychlorinated biphenyls (PCBs) are known to have different routes and degree of toxicity. Here, the effects of noncoplanar PCB 52 and coplanar PCB 77 present at 2 mol % in a model system consisting of POPC liposomes (50% hydrated) are investigated by solid-state (13)C and (31)P NMR at 298 K. Both PCBs intercalate horizontally in the outer part of the bilayer, near the segments of the acyl chain close to the glycerol group.

CoenzymeQ10 localizations in model membranes. A Langmuir monolayer study.

The interaction of coenzyme Q10 (CoQ10) in a monolayer of 1,2-dipalmitoyl-sn-glysero-3-phospho-L-choline (DPPC), in a monolayer of 1,2-dierucoyl-sn-glysero-3-phospho-L-choline (DEPC), in a monolayer of 1-palmitoyl-2-oleoyl-sn-glysero-3-phospho-L-serine (POPS) and in a monolayer of total lipid extract from pig brain (PB) has been investigated by using the Langmuir monolayer technique. Surface pressure (π)-mean molecular area (mma) isotherms have been measured for pure lipid monolayers and lipid monolayers with 0.5, 1.

Long-range surface-induced water structures and the effect of 1-butanol studied by 1H nuclear magnetic resonance.

Thin films of water between glass plates were investigated in this study with regard to water structure and dynamics in the temperature range of 278-313 K. We further investigated how addition of 1-butanol (0.05 and 0.

Interaction of local anaesthetic articaine enantiomers with brain lipids: a Langmuir monolayer study.

The interactions of the racemic mixture of articaine as well as pure (R)-articaine and pure (S)-articaine with monolayers of glycerophospholipids and brain lipids have been studied using the Langmuir monolayer technique. Articaine was added to the glycerophospholipids dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylserine (DPPS), 1-palmitoyl-2-oleoylphosphatidylserine (POPS) and total lipid extract from pig brain (TLPB). The amount of articaine in the monolayers was 30 mol%.

Thermotropic behavior of a cationic surfactant in the adsorbed and micellar state: an NMR study.

Knowledge about how temperature affects the internal structure and dynamics of surfactant aggregates can lead to a better understanding of their behavior in complex environments and processes. (13)C chemical shifts of the cationic surfactant tetradecytrimethylammonium bromide (TTAB) in micellar solution and when adsorbed on silica particles are recorded in the temperature range 8-78 °C, and give information on the conformation of the alkyl chain carbons. Adsorbed TTAB has conformational disorder similar to free TTAB at about 70 °C, with an increase in the rate of conformational changes occurring above 50 °C.

1H NMR relaxation of water: a probe for surfactant adsorption on kaolin.

In this study, (1)H NMR is used to investigate properties of sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB), and dodecyl trimethyl ammonium bromide (DTAB) adsorbed on kaolin by NMR T(1) and T(2) measurements of the water proton resonance. The results show that adsorbed surfactants form a barrier between sample water and the paramagnetic species present on the clay surface, thus significantly increasing the proton T(1) values of water. This effect is attributed to the amount of adsorbed surfactants and the arrangement of the surfactant aggregates.

Water structure and dynamics at a silica surface: Pake doublets in 1H NMR spectra.

Detailed knowledge about the dynamics and structure of liquids in the vicinity of a solid surface is important in several fields of research. In this study a homogeneous model system of colloidal and nonporous silica particles with a narrow particle size distribution was used to examine such properties of adsorbed water and 1-heptanol. Doublet (1)H water resonances ("Pake doublets") indicate a preferred spatial orientation for the water molecules, as well as a lower molecular density in the surface-induced water structures compared to bulk water.

Cisplatin interaction with phosphatidylserine bilayer studied by solid-state NMR spectroscopy.

Cisplatin [cis-diamminedichloridoplatinum(II)] is used in chemotherapy where platinum-DNA adducts initiate tumor cell death. It is possible that side effects such as neurotoxicity and cellular cisplatin resistance can be due to interaction of cisplatin with lipids and the phospholipid bilayer. In this study, (13)C, (31)P, and (15)N solid-state NMR spectra of 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) bilayers, POPS bilayers with 10 mol% cisplatin, and POPS bilayers with 30 mol% cisplatin were acquired.

Interaction of articaine hydrochloride with prokaryotic membrane lipids.

Objective: Local anesthetics are the most commonly used drugs in dentistry, with a wide range of effects, including antimicrobial activity. High antimicrobial effects have recently been reported on oral microbes from articaine hydrochloride, revealed by the minimum inhibitory concentration and minimal bactericidal concentration. Additionally, articaine has recently been used as an alkaline component in endodontic materials with a proposed antibacterial activity.

Anticancer cisplatin interactions with bilayers of total lipid extract from pig brain: A13C, 31P and 15N solid-state NMR study.

Cisplatin (cis-diamminedichloroplatinum(II)) is used in chemotherapy and it is well established that cisplatin forms platinum-DNA adducts that initiate tumor cell death. Drawbacks are side effects such as neurotoxicity and cellular cisplatin resistance and it is possible that part of these effects are linked to cisplatin interaction with lipids and the phospholipid bilayer. 13C magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of total lipid extract from pig brain with and without cisplatin show that the phosphatidylserine (PS) carboxyl resonance disappears in presence of cisplatin and that a new resonance of similar intensity appears at 185.

Articaine interaction with DSPC bilayer: a 13C and 31P solid-state NMR study.

Articaine hydrochloride, 4-methyl-3-(2-[propylamino]propionamido)-2-thiophenecarboxylic acid, methyl ester hydrochloride, is a local anaesthetic commonly used in dentistry, and is classified as an amide local anaesthetic. Solid-state (13)C and (31)P NMR were used to investigate the uncharged articaine species (sample pH 10.0) when interacting with distearoylphosphatidylcholine (DSPC) model membranes.

Olanzapine interaction with dipalmitoyl phosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) bilayer: a (13)C and (31)P solid-state NMR study.

Phospholipid bilayer interaction of olanzapine (OLZ), a thienobenzodiazepine derivative and an antipsychotic agent, has been studied with (13)C and (31)P solid-state NMR. A dipalmitoyl phosphatidylcholine (60%)/1-palmitoyl-2-oleoyl phosphatidylserine (40%) bilayer (DPPC(60%)/POPS(40%)) with 50 wt.% H(2)O, with and without 10 mol% OLZ have been investigated.

A general strategy for the rational design of size-selective mesoporous catalysts.

A series of functionalized mesoporous silicas with cagelike pore topology has been synthesized and screened for size-selective catalytic transformations. The aluminum-catalyzed Meerwein-Ponndorf-Verley (MPV) reduction of differently sized aromatic aldehydes (benzaldehyde and 1-pyrenecarbox-aldehyde) has been investigated as a test reaction. The catalysts were synthesized in a two-step grafting sequence comprising pore-size engineering of mesoporous silicas (SBA-1, SBA-2, SBA-16) with long-chain alkyl dimethylaminosilanes and surface organoaluminum chemistry with triethylaluminum [{Al(CH(2)CH(3))3}2].

Existence of lipid microdomains in bilayer of dipalmitoyl phosphatidylcholine (DPPC) and 1-stearoyl-2-docosahexenoyl phosphatidylserine (SDPS) and their perturbation by chlorpromazine: a 13C and 31P solid-state NMR study.

The polyunsaturated fatty acid docosahexaenoic acid (DHA, 22:6, n-3) is found at a level of about 50% in the phospholipids of neuronal tissue membranes and appears to be crucial to human health. Dipalmitoyl phosphatidylcholine (DPPC, 16:0/16:0 PC) and the DHA containing 1-stearoyl-2-docosahexenoyl phosphatidylserine (SDPS) were used to make DPPC (60%)/SDPS (40%) bilayers with and without 10 mol% chlorpromazine (CPZ), a cationic, amphiphilic phenothiazine. Resonances that are present in 13C NMR spectrum of the DPPC (60%)/SDPS (40%) sample and that disappear in presence of 10% CPZ most probably are due to the special interface environment, e.

Importance of polyunsaturated acyl chains in chlorpromazine interaction with phosphatidylserines: a 13C and 31P solid-state NMR study.

The polyunsaturated fatty acid docosahexaenoic acid (DHA, c22:6, n-3) is found at a level of about 50% in the phospholipids of neuronal tissue membranes and appears to be crucial to human health. Dipalmitoyl phosphatidylcholine (DPPC, 16:0/16:0 PC), 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) and the DHA containing 1-stearaoyl-2-docosahexenoyl phosphatidylserine (SDPS) were used to make DPPC (60%)/POPS (29%)/SDPS (11%) bilayers with and without 10 mol% chlorpromazine (CPZ), a cationic, amphiphilic phenothiazine. The T1 relaxation measurements make it clear that the saturated acyl chains carbons (palmitic, stearic and most of the oleic chain) and the choline head group are not affected by CPZ addition.

Chlorpromazine interaction with phosphatidylserines: a (13)C and (31)P solid-state NMR study.

Chlorpromazine (CPZ), a cationic, amphiphilic phenothiazine derivative is widely used as an antipsychotic drug because it antagonizes dopaminergic receptors. (13)C and (31)P solid-state NMR techniques were employed on phospholipid bilayers with and without CPZ. Phosphatidylserine from pig brain (PBPS), 1-palmitoyl-2-oleoyl phosphatidylserine (POPS), synthetic 1,2-dipalmitoyl phosphatidylcholine (DPPC) and chlorpromazineHCl were used to make phospholipid bilayers containing two types of phospholipids: DPPC (60%)/PBPS (40%) as well as POPS and PBPS bilayers without and with 10% CPZ.

Structural restraints and heterogeneous orientation of the gramicidin A channel closed state in lipid bilayers.

Although there have been several decades of literature illustrating the opening and closing of the monovalent cation selective gramicidin A channel through single channel conductance, the closed conformation has remained poorly characterized. In sharp contrast, the open-state dimer is one of the highest resolution structures yet characterized in a lipid environment. To shift the open/closed equilibrium dramatically toward the closed state, a lower peptide/lipid molar ratio and, most importantly, long-chain lipids have been used.

Chlorpromazine interaction with glycerophospholipid liposomes studied by magic angle spinning solid state (13)C-NMR and differential scanning calorimetry.

Phosphatidylserine (PS) extracted from pig brain and synthetic dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) were used to make DPPC/DMPC and DPPC/PS large unilamellar liposomes with a diameter of approximately 1 microm. Chlorpromazine-HCl (CPZ), an amphipathic cationic psychotropic drug of the phenothiazine group, is known to partition into lipid bilayer membranes of liposomes with partition coefficients depending on the acyl chain length and to alter the bilayer structure in a manner depending on the phospholipid headgroups. The effects of adding CPZ to these membranes were studied by differential scanning calorimetry and proton cross polarization solid state magic angle spinning (13)C-nuclear magnetic resonance spectroscopy (CP-MAS-(13)C-NMR).

Physical properties of the transmembrane signal molecule, sn-1-stearoyl 2-arachidonoylglycerol. Acyl chain segregation and its biochemical implications.

sn-1,2-diacylglycerol (DAG), a key intermediate in lipid metabolism, activates protein kinase C and is a fusogen. Phosphoinositides, the main sources of DAG in cell signaling, contain mostly stearoyl and arachidonoyl in the sn-1 and -2 positions, respectively. The polymorphic behavior of sn-1-stearoyl-2-arachidonoylglycerol (SAG) was studied by differential scanning calorimetry, x-ray powder diffraction, and solid state magic angle spinning (MAS) (13)C NMR.

Sequence-dependent binding of metal ion to DNA oligomeres. A comparison of molecular electrostatic potentials with NMR data.

Experimentally observed sequence-selective binding of metal ion to DNA oligonucleotides have been compared with variations of electrostatic potential (EP) along the helix. Calculations of EP have been performed for three atomic models of the oligonucleotide duplex [d(CGCGAATTCGCG)2] using several variants of EP calculations, including a solution of non-linear Poisson-Boltzmann equation (NPBE). N7 atom of guanine adjacent to adenine base was identified as a region with the most negative electrostatic potential in the major groove.

Interactions between Poly(Ethylene Oxide) and Sodium Dodecyl Sulfate as Studied by NMR, Conductivity, and Viscosity at 283.1-298.1 K.

The aggregation of sodium dodecyl sulfate (SDS) in aqueous solution containing a constant amount of poly(ethylene oxide) (PEO) at 2000 ppm has been investigated by several experimental techniques at three temperatures, 298.1, 288.1, and 283.