scholarly journals Competitive hydrogen bonds associated with the effect of primycin antibiotic on oleic acid as a building block of plasma membranes

2010 ◽  
Vol 63 (3) ◽  
pp. 113-117 ◽  
Author(s):  
Eszter Virág ◽  
Miklós Pesti ◽  
Sándor Kunsági-Máté
Keyword(s):  
Oleic Acid ◽  
Hydrogen Bonds ◽  
Building Block ◽  
Plasma Membranes

Wasserstruktur und Permeation: Die Aktivierungsenergie und der molekulare Mechanismus der Wasserpermeation

1967 ◽  
Vol 22 (8) ◽  
pp. 885-890 ◽  
Author(s):  
Josef Weigl
Keyword(s):  
Membrane Proteins ◽  
Hydrogen Bonds ◽  
Water Permeability ◽  
Plasma Membranes ◽  
Water Structure ◽  
Activation Energies ◽  
Membrane Properties ◽  
Pure Liquid ◽  
Tissue Water ◽  
Prolonged Contact

The exchange of tissue water of corn roots with ambient water was investigated using D2O, a gaschromatographic method, and a technique which avoids prolonged contact of tissue water with atmospheric water.The exchange experiments were performed at 10°, 20°, and 25 °C and the activation energies for different exchange phases were calculated by a method involving a graphical determination of the relative exchange rates at certain H2O/D2O gradients. Log10 of the rates were plotted versus 1/T as usual and the activation energies were calculated from the slopes of the straight lines. The energy of activation of the exchange process increased from 4.4 kcal-mol-1 in an initial phase (exchange of surface water and free space water) to 6.3 kcal·mol-1 in later phases which represent the processes of permeation through plasma and plasma membranes. This suggests that the hydrogen bonds of permeating water have a mean energy of 6 —7 kcal·mol-1 resulting from interaction with membrane (and plasma) constituents.The theory is proposed that cell membranes contain water phases with hydrogen bonds stronger than those in pure liquid water. These water phases are assumed to be located mainly within apolar portions of globular membrane proteins. Not solely a continous lipid layer, but a specific arrangement of polar and apoiar portions of globular membrane proteins is regarded to be essential for semipermeability and other membrane properties. Results from various authors were considered in establishing the general working hypothesis that agents like apoiar compounds which increase water structure decrease water permeability, and agents like salts which disrupt water structure increase water permeability.

The first structurally analysed nucleic acid building block containing the Reese protecting group: 2′-O-[1-(2-fluorophenyl)-4-methoxypiperidin-4-yl]-β-D-(1′R,2′R,3′R,4′R)-uridine

2015 ◽  
Vol 71 (5) ◽  
pp. 402-406
Author(s):  
Rafal Kruszynski ◽  
Wojciech Czestkowski
Keyword(s):  
Nucleic Acid ◽  
Hydrogen Bonds ◽  
Electron Density ◽  
Building Block ◽  
Title Compound ◽  
Considerable Degree ◽  
Two Dimensional ◽  
Protecting Group ◽  
Compound C ◽  
Group 2

The title compound, C21H26FN3O7, is assembled by N—H...O and O—H...O hydrogen bonds into well-separated two-dimensional layers of about 15 Å thickness. The crescent conformation of the molecules is stabilized by weak intramolecular C—H...O and C—H...F hydrogen bonds. The uridine moiety adopts ananticonformation. The ribofuranose ring exists in an envelope conformation. All the endocyclic uracil bonds are shorter than normal single C—N and C—C bonds, and five of them have comparable lengths, which implies a considerable degree of delocalization of the electron density within this ring.

The evolution of self-assemblies in the mixed system of oleic acid–diethylenetriamine based on the transformation of electrostatic interactions and hydrogen bonds

Soft Matter ◽  
2014 ◽  
Vol 10 (40) ◽  
pp. 8023-8030 ◽  
Author(s):  
Chengcheng Zhou ◽  
Xinhao Cheng ◽  
Oudi Zhao ◽  
Shuai Liu ◽  
Chenjiang Liu ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Hydrogen Bonds ◽  
Electrostatic Interactions ◽  
Mixed System

(1R,3R)-1,3-Dimethyl-8-hydroxy-6- methoxy-1,2,3,4-tetrahydroisoquinoline Hydrochloride - an Enantiomerically Pure Building Block for the Synthesis of Naphthylisoquinoline Alkaloids

1995 ◽  
Vol 50 (7) ◽  
pp. 1137-1140 ◽  
Author(s):  
Karl Peters ◽  
Eva-Maria Peters ◽  
Gerhard Bringmann ◽  
Paul Anthony Keller ◽  
Manuela Schäffer
Keyword(s):  
Hydrogen Bonds ◽  
Building Block ◽  
Title Compound ◽  
Enantiomerically Pure ◽  
Orthorhombic System ◽  
Space Group ◽  
Naphthylisoquinoline Alkaloids

The title compound was prepared by hydrogenolytic deprotection of the corresponding Nbenzyl derivative, which had previously been synthesized by a Picted-Spengler condensation of the corresponding arylethylamine. It crystallizes from dichloromethane/methanol in the orthorhombic system, space group P212121 ; a = 1305.7(2), b = 1400.3(3), c = 727.4(1) pm. Hydrogen bonds between Cl and OH and NH2 groups cause a threedimensional arrangement.

scholarly journals Phospholipid-Cellulose Interactions: Insight from Atomistic Computer Simulations for Understanding the Impact of Cellulose-Based Materials on Plasma Membranes

2018 ◽  
Author(s):  
Andrey A. Gurtovenko ◽  
Evgenii I. Mukhamadiarov ◽  
Andrei Yu. Kostritskii ◽  
Mikko Karttunen
Keyword(s):  
Hydrogen Bonds ◽  
Plasma Membranes ◽  
Md Simulations ◽  
Umbrella Sampling ◽  
Atomic Scale ◽  
Pronounced Difference ◽  
Dominant Component ◽  
Head Groups ◽  
The Impact ◽  
Cellulose Surface

AbstractCellulose is an important biocompatible and nontoxic polymer widely used in numerous biomedical applications. The impact of cellulose-based materials on cells and, more specifically, on plasma membranes that surround cells, however, remains poorly understood. To this end, here we performed atomic-scale molecular dynamics (MD) simulations of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) bilayers interacting with the surface of a cellulose crystal. Both biased umbrella sampling and unbiased simulations clearly show the existence of strong attractive interactions between phospholipids and cellulose: the free energy of the cellulose-bilayer binding was found to be −1.89 and −1.96 kJ/mol per cellulose dimer for PC and PE bilayers, respectively. Although the values are similar, there is a pronounced difference between PC and PE bilayers. The driving force in both cases is the formation of hydrogen bonds. There are two distinct types of hydrogen bonds: 1) between the lipid head groups and the hydroxyl (hydroxymethyl) groups of cellulose, and 2) lipid-water and cellulose-water bonds. The former is the dominant component for PE systems whereas the latter dominates in PC systems. This suggests that achieving controlled binding via new cellulose modifications must pay close attention to the lipid head groups involved. The observed attractive phospholipid-cellulose interactions have a significant impact on bilayer properties: a cellulose crystal induces noticeable structural perturbations on the bilayer leaflet next to the crystal. Given that such perturbations can be undesirable when it comes to the interactions of cellulose-based materials with cell membranes, our computational studies suggest that the impact of cellulose could be reduced through chemical modification of the cellulose surface which prevents cellulose-phospholipid hydrogen bonding.

scholarly journals Parallel-stacked aromatic molecules in hydrogen-bonded inorganic frameworks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Masayasu Igarashi ◽  
Takeshi Nozawa ◽  
Tomohiro Matsumoto ◽  
Fujio Yagihashi ◽  
Takashi Kikuchi ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Building Block ◽  
Materials Science ◽  
Chemical Space ◽  
Three Dimensional ◽  
Inorganic Materials ◽  
Orthosilicic Acid ◽  
Aromatic Molecules ◽  
Pure Benzene ◽  
Hydrogen Bonded

AbstractBy precisely constructing molecules and assembling these into well-defined supramolecular structures, novel physical properties and functionalities can be realized, and new areas of the chemical space can be accessed. In both materials science and biology, a deeper understanding of the properties and exploitation of the reversible character of weak bonds and interactions, such as hydrogen bonds and π–π interactions, is anticipated to lead to the development of materials with novel properties and functionalities. We apply the hydrogen-bonded organic frameworks (HOFs) strategy to inorganic materials science using the cubic octamer of orthosilicic acid, [Si8O12][OH]8, as a building block, and find that various types of hydrogen-bonded inorganic frameworks (HIFs). We succeed in parallel π-stacking pure benzene, thiophene, selenophene, p-benzoquinone, thiophene·p-benzoquinone, and benzene·p-benzoquinone polymers infinitely. These polymers interact via their π-systems by taking advantage of the flexible pores of the three-dimensional nano-honeycomb HIFs, which consist of periodic wide and narrow segments.

The influence of oleic acid on cAMP accumulation of thyroid plasma membrane activated by thyrotropin

1988 ◽  
Vol 117 (1) ◽  
pp. 125-129
Author(s):  
Tien-Chun Chang ◽  
Tien-Shang Huang
Keyword(s):  
Plasma Membrane ◽  
Oleic Acid ◽  
Thyroid Hormone ◽  
Plasma Membranes ◽  
Albumin Concentration ◽  
Adenylate Cyclase System ◽  
Camp Accumulation ◽  
Hormone Binding ◽  
High Oleic ◽  
Oleic Acid Concentration

Abstract. Several thyroid hormone binding inhibitors have been described in nonthyroid illness. One of the major inhibitors, oleic acid, is present in excess amounts in sera of patients with nonthyroid illness. In this study, we demonstrated that oleic acid inhibited the cAMP accumulation of thyroid plasma membrane activated by thyrotropin at 50 μmol/l and higher concentrations. In the presence of albumin, oleic acid significantly inhibited the cAMP accumulation of plasma membrane activated by thyrotropin at 2.4 mmol/l (P < 0.01 when the albumin concentration was 40 g/l and pH was 7.4; P < 0.001 when the albumin concentration was 20 g/l and pH was 7.2). These findings suggest that in nonthyroid illness, especially at a low albumin concentration and low blood pH, a high oleic acid concentration may influence the thyroid function directly in addition to inhibiting the thyroid hormone binding to serum protein. Oleic acid also could inhibit 5′-guanylylimidodiphosphate- and forskolin-induced cAMP production in thyroid plasma membranes. Therefore, the inhibiting effect of oleic acid may be through the action of oleic acid on the catalytic unit of the hormone-sensitive adenylate cyclase system.

scholarly journals Crystal structure of poly[(4-aminopyridine-κN)(N,N-dimethylformamide-κO)(μ3-pyridine-3,5-dicarboxylato-κ3N:O3:O5)copper(II)]

2016 ◽  
Vol 72 (4) ◽  
pp. 440-443
Author(s):  
Cheng-Chen Shen ◽  
Xiu-Ni Hua ◽  
Lei Han
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Building Block ◽  
Title Compound ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Coordination Geometry ◽  
Secondary Building Unit ◽  
Metal Organic

The title compound, [Cu(C7H3NO4)(C5H6N2)(C3H7NO]n, is an amino-functionalized chiral metal–organic framework with (10,3)-atopology. It has been constructedviathe assembly of the achiral triconnected pyridine-3,5-dicarboxylate (3,5-PDC) building block and a triconnected CuIIatom. Each CuIIion is coordinated by two O atoms and one N atom, respectively, of three crystallographically independent 3,5-PDC ligands. The square-pyramidal (CuN2O3) coordination geometry of the CuIIion is completed by an N atom of a terminal 4-aminopyridine (4-APY) ligand and the O atom of a terminalN,N-dimethylformamide (DMF) ligand to give a triconnected `T'-shaped secondary building unit, which becomes trigonal in the resulting (10,3)-atopology. In the three-dimensional structure, weak N—H...O hydrogen bonds are observed in which the donor N—H groups are provided by the 4-APY ligands and the acceptor O atoms are provided by the non-coordinating carboxylate O atoms of the 3,5-PDC ligands.

3,6,9,16,19,22-Hexaazatricyclo[22.2.2.211,14]triconta-1(26),11(29),12,14(30),24,27-hexaene, C24H38N6, as a building block in supramolecular chemistry: structures in two and three dimensions

2000 ◽  
Vol 56 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Christopher Glidewell ◽  
George Ferguson ◽  
Richard M. Gregson ◽  
Alan J. Lough
Keyword(s):  
Hydrogen Bonds ◽  
Supramolecular Chemistry ◽  
Building Block ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Single Type ◽  
Water Molecules ◽  
Minor Components ◽  
Cation Site ◽  
Cation Sites

The adduct (1) formed between the hexaaza macrocycle 3,6,9,16,19,22-hexaazatricyclo[22.2.2.211,14]triconta-1(26),11(29),12,14(30),24,27-hexaene, C24H38N6, and 4,4′-sulfonyldiphenol, O2S(C6H4OH)2, is a salt [(C24H40N6)2+]·2[(HOC6H4SO2C6H4O)−], and the adduct (2) formed by the same macrocyclic amine with 4,4′-biphenol is an aquated salt which also contains neutral biphenol molecules, [(C24H40N6)2+]·2[(HOC6H4C6H4O)−]·(HOC6H4C6H4OH).2H2O. In both compounds the cations lie across centres of inversion: there are two crystallographically distinct cation sites in (1) and the conformations of the cations occupying them are quite different. In (2) the single type of cation site is occupied by a conformationally disordered cation: the major and minor components represent two further distinct conformers. In (1) the anions are linked by O—H...O hydrogen bonds into chains, and each cation is linked by a total of six N—H...O hydrogen bonds to anions in four different chains, so linking the chains into continuous sheets. In (2) the anions and the water molecules are linked into sheets, which are further linked into a continuous three-dimensional framework by both the cations and the neutral biphenol units.

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