Theory of cylindrical tubules and helical ribbons of chiral lipid membranes

Selinger, Jonathan V.; MacKintosh, F. C.; Schnur, Joel M.

doi:10.1103/physreve.53.3804

Cited by 180 publications

(230 citation statements)

References 46 publications

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“…The strong contrast shadow of the platinum coat also suggests the hollow tubular structure. Similar lipid right-handed helical tubular nano-and microstructures have been reported (26,27). B and C show a three-way junction and many three-way junctions, respectively.…”

Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞supporting

confidence: 79%

“…Spector et al (26) also used circular dichroism to study the chirality of diacetylenic lipid tubules formed from lipid bilayer membranes. Schnur and coworkers (26,27) developed a theory based on molecular chirality to explain the presence of helical markings on the twist of lipid tubules.…”

Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞mentioning

confidence: 99%

“…Furthermore, the strong contrast shadow of the platinum coat also suggested that the tubes are hollow, similar to the lipid microtubes. These surfactant peptides may form tubular structures akin to those found in lipid systems (27). Individual peptides are intrinsically twisted such that assembled structures will likely have a curvature.…”

Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞mentioning

confidence: 99%

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Molecular self-assembly of surfactant-like peptides to form nanotubes and nanovesicles

Vauthey

Santoso

Gong

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

789

701

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Several surfactant-like peptides undergo self-assembly to form nanotubes and nanovesicles having an average diameter of 30 -50 nm with a helical twist. The peptide monomer contains 7-8 residues and has a hydrophilic head composed of aspartic acid and a tail of hydrophobic amino acids such as alanine, valine, or leucine. The length of each peptide is Ϸ2 nm, similar to that of biological phospholipids. Dynamic light-scattering studies showed structures with very discrete sizes. The distribution becomes broader over time, indicating a very dynamic process of assembly and disassembly. Visualization with transmission electron microscopy of quickfreeze͞deep-etch sample preparation revealed a network of openended nanotubes and some vesicles, with the latter being able to ''fuse'' and ''bud'' out of the former. The structures showed some tail sequence preference. Many three-way junctions that may act as links between the nanotubes have been observed also. Studies of peptide surfactant molecules have significant implications in the design of nonlipid biological surfactants and the understanding of the complexity and dynamics of the self-assembly processes.amino acids ͉ charged and hydrophobic residues ͉ nonlipid surfactants ͉ simplicity to complexity ͉ prebiotic enclosures M olecular self-assembly recently has attracted considerable attention for its use in the design and fabrication of nanostructures leading to the development of advanced materials (1, 2). The self-assembly of biomolecular building blocks plays an increasingly important role in the discovery of new materials and scaffolds (3, 4), with a wide range of applications in nanotechnology and medical technologies such as regenerative medicine and drug delivery systems (5, 6). Recently, Hartgerink et al. (7) reported the design of a chimeric material consisting of a hydrophobic alkyl tail and a hydrophilic peptide containing phosphorylated serine with an RGD motif that facilitates directional alignment of mineralization of hydroxyapatite.We previously described a class of ionic self-complementary peptide that spontaneously self-assemble to form interwoven nanofibers in the presence of monovalent cations (8 -10). These nanofibers further form a hydrogel consisting of greater than 99.5% water. The constituent of the hydrogel scaffold is made of peptides with alternating hydrophilic and hydrophobic amino acids. Such a sequence has a tendency to form an unusually stable ␤-sheet structure in water (8 -10). When the peptides form a ␤-sheet, they exhibit two surfaces, a hydrophilic surface consisting of charged ionic side chains and a hydrophobic surface with hydrophobic side chains. As a result, the self-assembly of these peptides is facilitated by electrostatic interactions on one side and the hydrophobic interaction on the other, in addition to the conventional ␤-sheet hydrogen bond along the backbones. The self-assembling peptide scaffolds have been demonstrated to serve as substrate for tissuecell attachment, extensive neurite outgrowth, and formation of active n...

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Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞supporting

confidence: 79%

Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞mentioning

confidence: 99%

Section: Tem Examination Of Samples Prepared Through the Quick-freeze͞mentioning

confidence: 99%

See 1 more Smart Citation

Molecular self-assembly of surfactant-like peptides to form nanotubes and nanovesicles

Vauthey

Santoso

Gong

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

789

701

View full text Add to dashboard Cite

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“…[19][20][21][22][23][24][25][26][27][28][29] The mechanisms leading to chiral structures have been matter of intense research. Initial theoretical studies date from the late 1980's, early 1990's, [30][31][32] but the general rationale describing the morphological evolution of micelles to twisted and helical ribbons, and finally to nanotubes has only recently started to be unraveled by combining a variety of experimental, theoretical and structural approaches. [33][34][35][36]14 Despite such an important amount of research, it is still nowadays impossible to predict in advance the type of assembly that a given amphiphile will form and under which conditions this will occur.…”

Section: Introductionmentioning

confidence: 99%

pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants

et al. 2014

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International audienceIn the present paper, we show that the saturated form of acidic sophorolipids, a family of industrially scaled bolaform microbial glycolipids, unexpectedly forms chiral nanofibers only at pH below 7.5. In particular, we illustrate that this phenomenon derives from a subtle cooperative effect of molecular chirality, hydrogen bonding, van der Waals forces and steric hindrance. The pH-responsive behaviour was shown by Dynamic Light Scattering (DLS), pH-titration and Field Emission Scanning Electron Microscopy (FE-SEM) while the nanoscale chirality was evidenced by Circular Dichroism (CD) and cryo Transmission Electron Microscopy (cryo-TEM). The packing of sophorolipids within the ribbons was studied using Small Angle Neutron Scattering (SANS), Wide Angle X-ray Scattering (WAXS) and 2D H-1-H-1 through-space correlations via Nuclear Magnetic Resonance under very fast (67 kHz) Magic Angle Spinning (MAS-NMR)

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“…The nearly racemic DC(8,9)PC core handedness ratio corresponds to an Ising regime where E chiral core , the energy difference between tilt directions selected by a chiral DC (8,9)PC molecule in a tubule core nuclei, is small. However, a comprehensive theoretical description of tubule structure must abandon the general assumption that the helically wound core and exterior ribbons are equilibrium structures (17)(18)(19)(20)(21)(22)(23). Tubule cores grow rapidly (Ϸ1 m͞s axial growth) from supercooled spherical L ␣ -phase vesicles, whereas tubule exteriors' order-of-magnitude slower growth is fed by the cooling DC(8,9)PC-saturated solution (1).…”

mentioning

confidence: 99%

Chiral tubule self-assembly from an achiral diynoic lipid

Pakhomov

Hammer

Mishra

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Tubules possessing m-scale chiral substructure self-assemble from an achiral isomer of the tubule-forming diynoic phosphatidylcholine, 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine [DC(8,9)PC], showing that molecular chirality is not essential for tubule formation. CD spectroscopy shows that these structures' helical sense of handedness instead originates in a spontaneous cooperative chiral symmetry-breaking process. We conclude that the chiral symmetry-breaking must originate in the unusual feature common to the chiral and achiral tubule-forming molecules, the diynes centered in their hydrocarbon tails.T he chiral diynoic phosphatidylcholine 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine [DC(8,9)PC] (compound 1 of Fig. 1) self-assembles in ethanolic solutions to form microscopic (Ϸ0.5 m ϫ Ϸ30 m) hollow cylinders possessing an exterior helical trace similar to that found on a paper drinking straw. This trace is a remnant of the helical winding of a uniform-width phospholipid ribbon that forms tubules, and its helical sense of handedness is determined by the molecule's chirality: R-DC (8,9)PC form tubules possessing right-and left-handed exterior helical traces, respectively.The striking molecular chirality͞helical handedness correspondence has led to the idea that tubule formation is driven by molecular chirality. In the so-called ''chiral packing'' class of tubule formation and structure theories, the tubule-forming molecule's chiral shape causes the directors of neighboring molecules in the close-packed phospholipid bilayer membrane to be offset by a small angle. The cumulative effect of this director tilt is a helical twist along the membrane that results in the winding of the membrane to form closed cylinders. However, it has been recently shown that the L ␤Ј -phase helical ribbons that grow from enantiopure L ␣ -phase spherical vesicles are a nearly racemic mix of left-and right-handed helices (1). Minutes after the sphere-to-tubule transition is complete, lipid from the stillcooling DC(8,9)PC-saturated solution completely ensheaths the vesicle-derived helices through the coaxial helical growth of a second, outer cylinder. Paradoxically, whereas the core handedness ratio is nearly racemic, the outer cylinders have a uniform helical sense of handedness that corresponds to DC(8,9)PC chirality. Similar results have been obtained with two enantiomerically pure DC(8,9)PC analogs in which the phosphoryl oxygen linking the phosphatidylcholine headgroup to the chiral glycerol backbone has been removed or replaced by a methylene (-CH 2 -) group (2, 3). That three molecules possessing different chiral centers each produce nearly racemic helix handedness ratios suggests that the helices are not macroscopic expressions of molecular chirality. Instead, this apparently random membrane chiralization suggests a chiral symmetry-breaking mechanism that is a consequence of the L ␣ -to-L ␤Ј phase transition from which the helices form.Additional support for chiral symmetry-breaking models comes from studie...

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Theory of cylindrical tubules and helical ribbons of chiral lipid membranes

Cited by 180 publications

References 46 publications

Molecular self-assembly of surfactant-like peptides to form nanotubes and nanovesicles

Molecular self-assembly of surfactant-like peptides to form nanotubes and nanovesicles

pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants

Chiral tubule self-assembly from an achiral diynoic lipid

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