FORMATION OF HELICAL SUPER STRUCTURE FROM SINGLE-WALLED BILAYERS BY AMPHIPHILES WITH OLIGO-<scp>l</scp>-GLUTAMIC ACID-HEAD GROUP

Yamada, Kimiho; Ihara, Hirotaka; Ide, Toshio; Fukumoto, Takanori; Hirayama, Chuichi

doi:10.1246/cl.1984.1713

Cited by 155 publications

(92 citation statements)

References 12 publications

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“…4). from four pigment gallstone patients (CSI = 88-237%) also disclosed cholesterol filaments within 1- (29)(30)(31)(32)(33)(34)(35)(36). The needlelike habit is highly suggestive of anhydrous crystallization ( 11), which might be the case because in cholesterol-rich vesicles, the 3-3 hydroxyl group of cholesterol and the sn-2 carbonyl of lecithin can be hydrogen bonded (37,38).…”

Section: Resultsmentioning

confidence: 99%

Filamentous, helical, and tubular microstructures during cholesterol crystallization from bile. Evidence that cholesterol does not nucleate classic monohydrate plates.

Konikoff¹,

Chung²,

Donovan³

et al. 1992

J. Clin. Invest.

152

101

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Precipitation of cholesterol in gallbladder bile is believed to produce platelike cholesterol monohydrate crystals directly. We report complementary time-lapse microscopic studies of cholesterol crystallization from model bile that reveal initial assembly offilamentous cholesterol crystals covered by a monomolecular layer of lecithin. Over a few days, the filaments evolved through needle, helical, and tubular microstructures to form classical platelike cholesterol monohydrate crystals. Similar crystallization phenomena were observed in human gallbladder biles from cholesterol but not pigment stone patients. Synchrotron x-ray diffraction of the earliest filaments suggested a cholesterol monohydrate polymorph or admixture with an anhydrous cholesterol precursor. However, density gradient centrifugation of filamentous crystals revealed that their density was 1.032 g / ml, consistent with anhydrous cholesterol. Conventional x-ray diffraction of transitional crystalline forms was consistent with pure cholesterol monohydrate crystals, as were the equilibrium platelike crystals. These novel findings suggest that crystalline cholesterol in bile may not be completely mature or hydrated initially, but undergoes a series of transformations to become thermodynamically stable monohydrate plates. These observations have important implications for understanding the control of cholesterol crystallization in bile, as well as explaining putative crystal cytotoxicity during gallstone formation. (J. Clin. Invest. 1992. 90:1155-1160

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Section: Resultsmentioning

confidence: 99%

Filamentous, helical, and tubular microstructures during cholesterol crystallization from bile. Evidence that cholesterol does not nucleate classic monohydrate plates.

Konikoff¹,

Chung²,

Donovan³

et al. 1992

J. Clin. Invest.

152

101

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“…On the other hand, we investigated the property of chiral assemblies formed from amphiphiles with polypeptide-head groups. It was previously reported that compounds la-ld can form micelles with structural asymmetries such as ahelical4 and {3-sheet peptide-head groups, 5 and 2 can form helical superstructures composed of single-walled bilayer membranes. 6 la: R = (CH 2 ) 4 NH 2 (m + n = 3,8, 13 and 18) lb: =CH 3 (m= I, n= 10) lc: =CH 2 C 6 H 5 (m= I, n= 12) ld: =CH 2 CH(CH 3 ) 2 (m=9, n=9) * To whom correspondence should be addressed.…”

mentioning

confidence: 99%

Amphiphiles with Polypeptide-Head Groups III. Regulation of Enantioseiectivity in Micellar Hydrolysis

Ihara

Ide

Hotta

et al. 1986

Polym J

Self Cite

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ABSTRACT:Chiral ester cleavage by achiral hydroxamic acids was investigated in the presence of chiral matrix micelles formed from amphiphiles with poly-L-lysine-head groups. The results are summarized as follows. (I) The enantioselectivity was not observed in the alkaline hydrolysis in chiral micelles only. This matrix possesses no selectivity. When an achiral hydroxamic acid was added to the system, selectivity was induced. (2) The direction of selectivity is reversed by the conformational change of the secondary structure formed by the peptide moiety of matrix micelles. L-Selectivity in the random coil and D-selectivity in the cc-helix condition were observed. (3) The degree of selectivity is dependent on the chemical structure of hydroxamic acid; for example, an N-H type hydroxamic acid gives higher selectivity than an N-methyl type one. Thus, it is supposed that enantioselectivity is introduced by the chiral interaction between chiral micelles and achiral nucleophiles, in which the conformation of polypeptide moiety plays an important role.KEY WORDS Amphiphile I Surfactant I Micelle I Enzyme Model I Hydroxamate I Enantioselectivity I Polypeptide I Poly-L-lysine I cc-Helix I Random Coil I Many hydrolysis reactions of chiral esters catalyzed by amino acid-derivatives have been studied in micellar systems in order to mimic the enantioselectivity of enzyme reactions. 1 -3 These studies have proposed or proved that the structural fitting between a catalyst and a substrate is a significant factor to give high enantioselectivity. However, in spite of the recognition that the secondary structure of an enzyme plays a part in the specificity, the relation between the secondary structures and enantioselectivity is not yet clear. On the other hand, we investigated the property of chiral assemblies formed from amphiphiles with polypeptide-head groups. It was previously reported that compounds la-ld can form micelles with structural asymmetries such as ahelical4 and {3-sheet peptide-head groups, 5 and 2 can form helical superstructures composed of single-walled bilayer membranes. (m= I, n= 10) lc: =CH 2 C 6 H 5 (m= I, n= 12) ld: =CH 2 CH(CH 3 ) 2 (m=9, n=9)

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“…51,52 At almost the same time in 1984, three independent research groups in the USA and Japan first found the formation of lipid nanotubes on the basis of this chiral molecular self-assembly. 50,53,54 The self-assembled nanotube formation from the glucoside and glucosamide lipids described later is based on this mechanism. The second growing mechanism of self-assembled nanotubes has been reported for a limited number of examples.…”

Section: Introductionmentioning

confidence: 98%

Molecular Self-Assembly into One-Dimensional Nanotube Architectures and Exploitation of Their Functions

Shimizu¹

2008

Bulletin of the Chemical Society of Japan

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This review article focuses on the self-assembly of amphiphilic molecules into discrete, hollow cylindrical tubular architectures (organic nanotubes). Research on nanotube formation from dumbbell-shaped peptide lipids, 1-O-glucopyranoside and 1-N-glucopyranosylamide lipids, and wedge-shaped bolaamphiphilic glycolipids with carboxylic, amino, or oligoglycine groups at one end has been outlined with their characteristic self-assembly. Finally, recent progress in mass production, dimension control, and novel functions of organic nanotubes are described.

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FORMATION OF HELICAL SUPER STRUCTURE FROM SINGLE-WALLED BILAYERS BY AMPHIPHILES WITH OLIGO-l-GLUTAMIC ACID-HEAD GROUP

Abstract: Double-chain alkyl amphiphiles with oligo-l-glutamic acid-head group were prepared. These compounds were dispersed in water at pH 8 to 9 to form bilayer aggregates, in which helical and hollow structures were contained. New CD bands were observed in the solution.

Cited by 155 publications

References 12 publications

Filamentous, helical, and tubular microstructures during cholesterol crystallization from bile. Evidence that cholesterol does not nucleate classic monohydrate plates.

Filamentous, helical, and tubular microstructures during cholesterol crystallization from bile. Evidence that cholesterol does not nucleate classic monohydrate plates.

Amphiphiles with Polypeptide-Head Groups III. Regulation of Enantioseiectivity in Micellar Hydrolysis

Molecular Self-Assembly into One-Dimensional Nanotube Architectures and Exploitation of Their Functions

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