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Search for "membranes" in Full Text gives 196 result(s) in Beilstein Journal of Organic Chemistry.
Remarkable functions of sn-3 hydroxy and phosphocholine groups in 1,2-diacyl-sn-glycerolipids to induce clockwise (+)-helicity around the 1,2-diacyl moiety: Evidence from conformation analysis by 1H NMR spectroscopy
Beilstein J. Org. Chem. 2017, 13, 1999–2009, doi:10.3762/bjoc.13.196
- ; deuterium labeling; sn-glycerol; glycerolipids; glycerophospholipids; helicity; Karplus equation; proton NMR spectroscopy; staggered conformers; Introduction Glycerophospholipids, constituting the basic elements of cytoplasm bilayer membranes, are responsible for several cell functions [1][2][3]. These
- those examined under physiological conditions. For example, glycerophospholipids are located in self-assembled lamellar structures that show liquid crystalline properties. Plasma membranes comprise glycerophospholipids which interact with other membrane components such as glycoproteins and sterols [38
Block copolymers from ionic liquids for the preparation of thin carbonaceous shells
Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163
- are applied as catalytic membranes, thermotropic liquid crystals [12], polymer electrolytes, ionic conductive materials, CO2 absorbing materials, microwave absorbing materials and porous materials [4]. Most of these polymers were synthesized by free radical polymerization. There are just few reports
- conductivity [16]. There are many different morphologies of carbon achievable, like hallow carbon spheres [17], nanotubes, membranes and fibers [18]. Due to their charged nature the PILs show a low vapor pressure and are non-volatile, leading to high carbon yields [19]. Furthermore, PILs offer the possibility
Chemical systems, chemical contiguity and the emergence of life
Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155
- related to one aspect of cellular make-up, such as the formation of membranes or the build-up of information/catalytic apparatus. This approach is being gradually replaced by a more “systemic” approach that privileges processes inherent to complex chemical systems over specific isolated functional
- for the determination of environmental conditions conducive to the self-assembly of several cellular-like components, such as bilayer membranes [15] and simple energy systems [16], or dynamic processes, such as growth and division [17][18] and potential evolution [19]. However, the experimental set
- of RNAs for catalytic activity, which often requires the presence of high ion concentrations that are disruptive for the formation of primitive membrane models. Membranes composed of putatively prebiotic amphiphiles, such as single hydrocarbon chain species [20][21] may have been exemplars of such
2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization
Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148
- . Acknowledgements The German Federal Ministry of Education and Research (BMBF) is kindly acknowledged for financial support in the framework of the BMBF-Forschertandem “Chiral Membranes”. T.M.G. thanks the Alexander von Humboldt-Stiftung for financial support. We gratefully acknowledge the financial support by the
A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E
Beilstein J. Org. Chem. 2017, 13, 1430–1438, doi:10.3762/bjoc.13.140
- chain is of key importance for the antibiotic activity of the fusaricidins and their selective inhibition of bacterial cells due to the interaction with phospholipid cell membranes [1]. Genetic analysis of the producing organisms suggests that the biosynthesis of this essential part of the fusaricidins
Framing major prebiotic transitions as stages of protocell development: three challenges for origins-of-life research
Beilstein J. Org. Chem. 2017, 13, 1388–1395, doi:10.3762/bjoc.13.135
- variety of processes that take place across their boundaries – lipid membranes in/on which highly sophisticated mechanisms of transport and energy transduction reside, making possible the maintenance of the system, as a whole, in open, far-from-equilibrium conditions. In a metaphoric sense, a cell is a
- inside semi-permeable membranes [43]. For these reasons, an early ‘co-evolutionary’ scenario in which membranes and internal chemistries develop ‘hand-in-hand’, tightly linked and supportive to each other, makes more sense (see also [44]). Hence our first corollary, expressed in terms of a challenge for
- stability, the permeability/fluidity of their membranes) and displacing them, as a result, from their primary quasi-equilibrium states (e.g., inducing their growth and potential reproduction). In turn, vesicle dynamics should prove supportive of – or at least compatible with – that chemistry. Cell
Biomimetic molecular design tools that learn, evolve, and adapt
Beilstein J. Org. Chem. 2017, 13, 1288–1302, doi:10.3762/bjoc.13.125
- the sterol and fatty acid biosynthetic pathways were activated in the MSCs, and subsequent experiments validated the model predictions of increased levels of proteins in these pathways and the formation of lipid rafts on the cell membranes. In silico sparse feature selection thus revealed a hitherto
Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience
Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114
- constitution and dynamics of plasma membranes, the structural and physicochemical features of gangliosides have been somehow neglected presumably because of the lack of appropriate experimental techniques. X-ray reflectometry is a surface-sensitive analytical technique based on the measure of the intensity of
From chemical metabolism to life: the origin of the genetic coding process
Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111
- is not a fight against the second principle of thermodynamics), using the global distribution of water molecules as a driving force to order lipids into cell-like structures (of a considerable variety, even in bacteria [12]). Membranes also contain proteins as essential components. It took very long
- inserted into membranes is a thriving domain of research [13]. Membranes serve a variety of functions such as transport, sensing, protection or supporting movement. They are also involved in energy production via vectorial transport of ions, generally protons. Transport and management of energy imply
- implies the management of construction and maintenance within a 2D structure, while the metabolism that develops in the cytoplasm and produces the building blocks for membranes and their proteins is expressed in three dimensions (3D). Matching the syntheses in both compartments is not a trivial matter
Correlation of surface pressure and hue of planarizable push–pull chromophores at the air/water interface
Beilstein J. Org. Chem. 2017, 13, 1099–1105, doi:10.3762/bjoc.13.109
- directionally into lipid bilayer membranes. In order to use fluorescent flipper mechanophores for biological measurements, it is crucial to understand the exact relation between surface pressure and their spectroscopic properties. In earlier studies [8], the fluorescence was qualitatively determined in
- . Monolayers at the air/water interface are well known models for biological membranes, avoiding trans-bilayer leaflet correlation effects [11][12][13][14]. Various techniques exist to probe the surface pressure and the lateral organization of the monolayer [14]. Using monolayers of pure flipper probes, we
- probes in bilayer membranes of increasing order [8]. Similar interpretations have been made for the spectral changes observed upon planarization of self-assembled mechanosensitive twisted phenylethynyl polymers [26]. Conclusion In conclusion, we have presented the first measurement correlating the hue of
Total syntheses of the archazolids: an emerging class of novel anticancer drugs
Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108
- biological targets and pathways [12][13]. Vacuolar-type ATPases (V-ATPases) are heteromultimeric proton translocating proteins that are localized in a multitude of eukaryotic membranes [14][15][16] that have been known as key mediators in a variety of biochemical pathways. They are responsible for a variety
Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates
Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101
- from Bio-Rad Laboratories, Inc. (Hercules, CA). 4-OT, 4-OD/VPH, and 4-OD/E106QVPH (all from P. putida mt-2) were purified by procedures reported elsewhere with minor modifications [10][11][19][20]. The YM-3 ultrafiltration membranes and centrifugal microconcentrators were obtained from Millipore
Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids
Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99
- bolalipids originate in membranes of some species of archaea, e.g., thermoacidophiles and these archaeal membranes can withstand extreme living conditions, such as high temperatures or low pH values [2][3][4]. Archaea are quite different from bacteria and eukaryotes [5][6][7][8][9], which is also reflected
- and that the PC-C18pPhC18-PC is partially miscible with these phospholipids. When ca. 10 or 20 mol % of bolalipid is inserted in membranes of phosphatidylcholines, disk-like structures are the dominant aggregate form. We can only speculate, whether both types of lipid molecules are randomly
A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE
Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98
- [6,6]-bicyclic lactone 26. Pharmacological evaluation The binding properties of two synthesized CD fragments (compounds 9 and 26) were characterized in a [3H]-epibatidine binding assay using membranes from HEK293 cells stably expressing the rat heteromeric nAChR subtypes α4β2, α4β4 and α3β4 as
Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic
Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97
Expression, purification and structural analysis of functional GABA transporter 1 using the baculovirus expression system
Beilstein J. Org. Chem. 2017, 13, 874–882, doi:10.3762/bjoc.13.88
- [1]. GATs, which are located in the plasma membranes of neurons and glia cells, belong to the solute carrier 6 (SLC6) family in mammals, which is subdivided into four groups based on sequence composition: GATs, GABA, osmolyte and creatine transporters, neurotransmitter amino acid, monoamine and
- at 4 °C. A turbid supernatant solution containing the cell membranes was obtained. After centrifugation at 100,000g at 4 °C for 30 min, the crude membrane fractions were solubilized in TBS containing 1% DDM and stirred for at least 4 h at 4 °C. The lysate was centrifuged at 18,000g at 4 °C for 1 h
Lipids: fatty acids and derivatives, polyketides and isoprenoids
Beilstein J. Org. Chem. 2017, 13, 793–794, doi:10.3762/bjoc.13.78
- was likely a crucial process for the origin of life – and certainly still is for all existing living systems that necessarily contain lipid membranes with their interesting and finely balanced biophysical properties. In prokaryotes, these membranes define the outer surface of individual cells, while
- in addition to that in eukaryotic organisms membranes are of utmost importance also for cell compartmentation, i.e., the inner structure of a cell. A large portion of these membranes is composed of steroids that influence membrane properties, such as fluidity and permeability, but have a
Membrane properties of hydroxycholesterols related to the brain cholesterol metabolism
Beilstein J. Org. Chem. 2017, 13, 720–727, doi:10.3762/bjoc.13.71
- influence on lipid chain order, membrane permeability and formation of lateral domains. Keywords: cholesterol; fluorescence; hydroxycholesterol; membrane structure; NMR; Introduction Cholesterol is a major component of mammalian cell membranes with various biological functions. It plays a key role in
- function, protein trafficking, and intramembrane proteolysis [1][2][3]. A large amount of cholesterol in the human body is located in the brain, where it constitutes an integral part of myelin membranes acting as electrical insulators [4]. Cholesterol is also a major component of the plasma membranes of
- their influence on lipid membranes have been widely investigated as a basis for the understanding of the cell biological importance of the molecule. It has been shown that the membrane properties of cholesterol are extremely well adapted to exert a very specific influence on the other membrane
Conjecture and hypothesis: The importance of reality checks
Beilstein J. Org. Chem. 2017, 13, 620–624, doi:10.3762/bjoc.13.60
- organic compounds that are then incorporated into a primitive metabolism [12]. Lane and Martin [13] noted that the alkaline vent minerals have a porous structure that could serve as cellular compartments with mineral membranes as boundaries. The assumption that the membranes may separate a strongly
Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands
Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55
- transport of anions through lipid membranes [19][20][21][22]. Some of similar pincer compounds can be used as receptors for organic molecules; e.g., polyamino derivatives based on cholane skeleton can form complexes with amino acids [23] and pincer-like conjugates of deoxycholic acid and aminopyrene can
- arylaminocholanes and cholane-diaminoanthraquinone derivatives by Pd- and Cu-catalyzed amination. Such compounds not only have cation binding properties, but also might be easily introduced in lipid membranes to form ion channels. Appropriate close location of lipophilic steroid fragments in bis(cholanediamino
- with copper cation in comparison to bidentate ligands 5c and 5d. However, the cholane skeleton in 5c and 5d can be useful for integration of these ligands into lipophilic membranes. Conclusion Cu- and Pd-catalyzed cross-coupling reactions were applied for the preparation of arylamino derivatives of
Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction
Beilstein J. Org. Chem. 2017, 13, 558–563, doi:10.3762/bjoc.13.54
- selectively dissolved using cyclohexane. Afterwards we dissolved the sacrificial substrate to obtain the freestanding CMP membranes. To investigate the freestanding CMP nanomembrane we transferred it to a copper grid and recorded scanning electron microscopy (SEM) images. Figure 4 shows the SEM images of the
- investigations. The thin films show high mechanical stability as evidenced by the possibility to create feestanding membranes across holes of about 3–5 µm diameter. The rapid and scalable synthetic method for CMP nanomembranes described in this article, along with the possibility to transfer the nanomembranes to
Synthesis of 1-indanones with a broad range of biological activity
Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48
- ]. Next, the latter was converted to 4,6-dibromo-5-hydroxy-1-indanone in the presence of a Lewis acid and then transformed to 5-hydroxy-1-indanone as a result of debromination. Adrenergic receptors are metabotropic receptors located on cell membranes and stimulated by catecholamines, especially adrenaline
Synthesis of multi-lactose-appended β-cyclodextrin and its cholesterol-lowering effects in Niemann–Pick type C disease-like HepG2 cells
Beilstein J. Org. Chem. 2017, 13, 10–18, doi:10.3762/bjoc.13.2
- cholesterol [25]. NPC2 interacts with NPC1 and delivers cholesterol to the limiting membranes [25], while β-CDs form inclusion complexes with cholesterol. Hence, β-CDs may have the potential to bypass the functional NPC1 or NPC2 and deliver cholesterol directly to the limiting membranes. Once the cholesterol
- exits the endolysosomes, it is delivered to other organelles by the cholesterol transport system. To elucidate the detailed mechanism of cholesterol-lowering effects of multi-Lac-β-CD (DSL5.6), further elaborate studies on not only the interaction of multi-Lac-β-CD (DSL5.6) with endolysosomes membranes
Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts
Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270
- ; membrane; Stokes shift; Introduction The membrane of living cells consists of a variety of lipids. More than 40 years ago, biological membranes were first described as Fluid Mosaic in which proteins were embedded [1]. During recent decades it became more and more clear that such a simple model is not
- ., differences in membrane thickness and stiffness, different diffusion coefficients etc.) [5][6]. Tools to investigate lipid membranes are multifaceted; however, all optical methods are hampered by the missing absorption and fluorescence properties of natural occurring lipid components. Therefore, indirect
- membranes. Results and Discussion Synthesis The most prominent methods to access oligoene structures are either cross-coupling reactions [17][18][19] or Wittig-type reactions [20][21][22]. The advantage of the latter ones is that they are often conducted at low temperatures and therefore are employed for
Interactions between cyclodextrins and cellular components: Towards greener medical applications?
Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261
- ]. As these criteria apply only to absorption by passive diffusion of compounds through cell membranes, the absorption of the native CDs and their hydrophilic derivatives are not allowed in their intact form and any cellular absorption, if it occurs, is by passive transport through cytoplasmic membranes
- (i.e., by transporter proteins) [41]. In contrast, lipophilic derivatives (e.g., ME-β-CD) interact more readily with membranes than the hydrophilic derivatives, they cannot readily permeate cell membranes (see below) [42]. Moreover, oral administration of alkylated CD derivatives, such as ME-β-CD, is
- , sterols, fat-soluble vitamins, phospholipids, mono-, di- and triglycerides, etc. Their amphiphilic nature causes the molecules of certain lipids to organize into liposomes when they are in aqueous medium. This property allows the formation of biological membranes. Indeed, cells and organelles membranes
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