Disease relevance of Micelles

• Based on past attempts at developing vaccines against retroviruses, the most feasible configuration will be the glycoprotein linked to its transmembrane protein and assembled into micelles or rosettes by hydrophobic bonding [1].
• With the aim of preparing a light-insensitive bacteriorhodopsin-like pigment, bacterio-opsin expressed in Escherichia coli was treated in phospholipid-detergent micelles with the retinal analog II, in which the C13-C14 trans-double bond cannot isomerize due to inclusion in a cyclopentene ring [2].
• Retinol-induced rabbit erythrocyte hemolysis has been found not to be caused by the oxidative disruption of erythrocyte membrane lipids initiated by retinol oxidation, but rather to arise from physical damage of the membrane micelle induced by penetration of retinol molecules [3].
• NMR structure of PW2 bound to SDS micelles. A tryptophan-rich anticoccidial peptide selected from phage display libraries [4].
• Studies using defective interfering virus particles, UV light-inactivated virus, and purified micelles of the viral glycoprotein indicated that infectious virus was not required for sensitization of target cells for immune recognition by the class II MHC-restricted CTL clones [5].

High impact information on Micelles

• The three-dimensional structure of the lipase-procolipase complex, co-crystallized with mixed micelles of phosphatidylcholine and bile salt, has been determined at 3 A resolution by X-ray crystallography [6].
• Results presented here demonstrate that a mixture of fatty acid and lysophosphatidylcholine forms a bilayer type of organisation even though the individual components form micelles when dispersed in an aqueous phase [7].
• The present study is a direct demonstration of Ca2+-induced release of Ca2+ from the SR of skinned cardiac cells treated with chlorotetracycline (CTC), a fluorescent chelate probe which enables changes in the amount of Ca2+ bound to a variety of biological membranes or micelles to be monitored [8].
• Here, the solution structure of the FYVE domain of the early endosome antigen 1 protein (EEA1) in the free state was compared with the structures of the domain complexed with PtdIns(3)P and mixed micelles [9].
• The molar ratio of the complex of profilin with PIP2 is 1:7 in micelles of pure PIP2 and 1:5 in bilayers composed largely of other phospholipids [10].

Chemical compound and disease context of Micelles

• Depletion of virion cholesterol apparently results through collision with PC vesicles rather than movement of cholesterol monomers or micelles through the aqueous phase, because PC vesicle-virion interaction in the presence of cholesterol oxidase did not result in substantial oxidation of translocated cholesterol [11].
• The major coat protein (gVIIIp) of bacteriophage M13 solubilized in sodium dodecyl sulfate (SDS) detergent micelles was used as a model system to study this protein in the lipid-bound form [12].
• Vaccinia profilin binds to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 4-monophosphate in micelles and large unilamellar vesicles, but not to phosphatidylserine or phosphatidylcholine [13].
• The membrane-proximal tryptophan-rich region of the HIV glycoprotein, gp41, forms a well-defined helix in dodecylphosphocholine micelles [14].
• Amphotericin B incorporated into egg lecithin-bile salt mixed micelles: molecular and cellular aspects relevant to therapeutic efficacy in experimental mycoses [15].

Biological context of Micelles

• Under simulated physiological conditions, hydrolysis of emulsified fat droplets by human pancreatic lipase in the presence of colipase and bile salt micelles proceeds with the sequential formation of two visible product phases [16].
• IGFBP-5 has been suggested to induce apoptosis by sequestering IGF-1 to casein micelles, thereby inhibiting its survival function [17].
• Rate enhancements for nitrosation were also observed in the presence of micelles of phosphatidylcholine and Triton X-100 [18].
• These studies support the concept that platelets, rather than phospholipid micelles, are the primary locus of prothrombin and Factor X activation in normal hemostasis [19].
• In this review, the molecular conformations of the individual lipid components of biliary micelles and vesicles (phospholipids, bile salts and cholesterol) obtained by high-resolution x-ray crystallographical analysis are described [20].

Anatomical context of Micelles

• Endotoxin exocytosed by Kupffer cells fractionated into two peaks, one with a smaller and one with a larger apparent micelle size than native endotoxin but both smaller than the retained lipopolysaccharide [21].
• Here we describe a soluble phospholipase A1 from bovine testis that preferentially hydrolyzes phosphatidic acid when assayed in Triton X-100 micelles [22].
• The uptake of cholesterol delivered by mixed micelles by confluent CaCo-2 cells was partially inhibited by Ezetimibe and nonabsorbable Ezetimibe analogues [23].
• Solubilization of egg yolk PC occurs in Na-trichloroacetate between 2 and 3 M and in Na-tribromoacetate between 1.5 and 2 M. The resulting optically clear solutions were found by gel exclusion chromatography to consist of micelles containing of the order of 10(2) lipid molecules which, according to 31P NMR, are undergoing rapid, isotropic motion [24].
• These data suggest that a peptide (3,000 to 19,000) in the larger subunit of gamma-glutamyltranspeptidase is responsible for its binding to Triton micelles and probably for holding the enzyme in the brush border membrane [25].

Associations of Micelles with chemical compounds

• Profilin isolated from platelets binds with high affinity to small clusters of phosphatidylinositol 4,5-bisphosphate (PIP2) molecules in micelles and also in bilayers with other phospholipids [10].
• After extraction with deoxycholate (DOC), C5b-7 has a sedimentation velocity of 36S which further suggests the occurrence of C5b-7 in the form of tetrameric protein micelles [26].
• Antibody binding to beta 2-GPI on the irradiated plates was competitively inhibited by simultaneous addition of cardiolipin (CL)-coated latex beads mixed together with beta 2-GPI but were unaffected by addition of excess beta 2-GPI, CL micelles, or CL-coated latex beads alone [27].
• Gel filtration and sucrose gradient sedimentation showed sLFA-3 to be a single highly glycosylated polypeptide chain in solution, while mLFA-3 formed micelles of 8 LFA-3 monomers [28].
• We have recently shown that lipopolysaccharide (LPS)-binding protein (LBP) is a lipid transfer protein that catalyzes two distinct reactions: movement of bacterial LPS (endotoxin) from LPS micelles to soluble CD14 (sCD14) and movement of LPS from micelles to reconstituted high density lipoprotein (R-HDL) particles [29].

Gene context of Micelles

• Phosphatidylinositol 4,5 bisphosphate (PIP(2)) micelles allowed WASp to activate actin nucleation by Arp2/3 complex, and this was further enhanced twofold by GTP-Cdc42 [30].
• Sarcolipin, the shorter homologue of phospholamban, forms oligomeric structures in detergent micelles and in liposomes [31].
• Enzymatic activity of cPLA2 was determined in cell-free reaction mixtures utilizing mixed micelles of 14C-phosphatidylcholine and Triton X-100 as the substrate [32].
• Here, we report ligand-binding properties and structural characteristics of the CXCR1 N-domain in solution and in detergent micelles that mimic the native membrane environment [33].
• Arf1 was shown to bind to PIP2 in Triton X-100 micelles with a Kd of 45 +/- 13 microM [34].

Analytical, diagnostic and therapeutic context of Micelles

• GTPase experiments with varying concentrations of p21 and constant concentrations of GAP and lipids indicate that the binding of GAP by the lipid micelles is responsible for the inhibition, a finding which was confirmed by fluorescence titrations and gel filtrations which show that the C-terminal domain of GAP is bound by lipid micelles [35].
• In model bile, cholesterol crystallization was preceded by the appearance of the following distinct microstructures: spheroidal micelles (3-5 nm), discoidal membrane patches (50-150 nm) often in multiple layers (2-10), discs (50-100 nm), and unilamellar (50-200 nm) and larger multilamellar vesicles (MLVs) [36].
• We have developed a novel drug delivery system that releases drug from stabilized micelles upon application of low-frequency ultrasound and that demonstrates efficacy using doxorubicin (Dox) to treat tumors in vivo [37].
• Circular dichroism spectroscopy performed in the membrane-mimetic medium of deoxycholate micelles indicated comparable alpha-helical contents of mutants I32V and A27T to wild-type protein [38].
• Enzyme kinetics using vesicles as well as optical titration using a micelle system with the detergent Tween 20 demonstrate that activation is correlated with the fraction of P450SCC in the high spin form [39].

References