Crystal structure of cholesterol monohydrate

Craven, B. M.

doi:10.1038/260727a0

Cited by 281 publications

(208 citation statements)

References 7 publications

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“…There has been no further refinement since the earlier report (Craven, 1976). The final carbon and oxygen parameters are in Table 1 ~f Within experimental error, the values of bond lengths and angles agree with those accurately determined for cholesteryl acetate (Sawzik & Craven, 1979).…”

Section: Pseudosymmetry In the Crystal Structuresupporting

confidence: 52%

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Pseudosymmetry in cholesterol monohydrate

Craven¹

1979

Acta Crystallogr B Struct Crystallogr Cryst Chem

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Section: Pseudosymmetry In the Crystal Structuresupporting

confidence: 52%

“…The crystal structure determination of cholesterol monohydrate has been reported, its biological significance discussed and a possible epitaxical relationship with hydroxyapatite has been pointed out (Craven, 1976). Crystallographic aspects of the structure of cholesterol monohydrate are now described in more detail.…”

Section: Introductionmentioning

confidence: 99%

Pseudosymmetry in cholesterol monohydrate

Craven¹

1979

Acta Crystallogr B Struct Crystallogr Cryst Chem

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“…For comparison, the unit cell parameters of ChM at room temperature are a ϭ 12.39 Å, b ϭ 12.41 Å, c ϭ 34.36 Å, ␣ ϭ 90.04 , ␤ ϭ 98.1 , ␥ ϭ 100.8 (26). The difference in the lattice constants at different temperatures and between the ribbons and ChM are within experimental errors, except for c. We wish to stress here that the unit cell dimension along the c axis of our strips is triple that of ChM.…”

Section: Resultsmentioning

confidence: 99%

Structure of cholesterol helical ribbons and self-assembling biological springs

Khaykovich

Hossain

McManus³

et al. 2007

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

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We report the results of x-ray-scattering studies of individual helical ribbons formed in multicomponent solutions of cholesterol solubilized by various surfactants. The solutions were chemically defined lipid concentrate (CDLC) and model bile. In these and many analogous multicomponent surfactant-cholesterol solutions, helical ribbons of two well defined pitch angles, namely 11°and 54°, are formed. We have suggested previously that this remarkable stability results from an underlying crystalline structure of the sterol ribbon strips. Using a synchrotron x-ray source, we have indeed observed Bragg reflections from individual ribbons having 11°pitch angle. We have been able to deduce the parameters of the unit cell. The crystal structure of these ribbons is similar to that of cholesterol monohydrate, with the important difference that the length of the unit cell perpendicular to the cholesterol layers is tripled. We discuss possible origins for this triplication as well as the connection between the crystalline structure and the geometrical form of the helical ribbons.crystal structure ͉ x-ray diffraction ͉ crystallization ͉ surfactants S elf assembly of helical ribbons in complex fluids is an interesting phenomenon, which poses fundamental questions about the molecular structure, elastic properties, and kinetic evolution of these objects. In particular, quaternary solutions, which contain cholesterol, nonionic surfactants, and lipids, spontaneously form helical ribbons with characteristic pitch angles of 11°and 54°. These helical ribbons are long rectangular strips, which curl along a cylindrical surface. These objects were discovered in human gallbladder bile, where they form spontaneously upon the dilution of bile. This dilution produces a solution supersaturated with respect to cholesterol (1). Formation of similar helical ribbons has been later reported in Ͼ20 different solutions with various sterols analogous to cholesterol, surfactants, and phospholipids or fatty acids (2). These helical ribbons form in a variety of axial lengths, widths, and radii. Remarkably, however, almost all have pitch angles of either 11°o r 54°. Several theoretical models have been proposed to explain the formation and properties of helical ribbons, which sometimes form in complex fluids containing chiral amphiphilic molecules (3-10). These theories were designed to describe the helical ribbons in solutions containing a single species of phospholipids, which can form bilayers. Therefore, the ribbons were modeled theoretically as fluid bilayers, where hydrophobic carbon chains are sandwiched between hydrophilic head groups. Calculations of the properties of such membranes are usually based on the curvature elasticity model (11), which is founded on general physical arguments about the dependence of the fluid membrane elastic free energy on its curvature. Based on this model, subsequent theories attempted to explain the geometrical and elastic properties of the helical ribbons. For example, the formation of helices is attributed to b...

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“…The phase with a stable repeat distance of 33.6 Å at all CHOL concentrations has been assigned to CHOL separated into CHOL monohydrate crystals [34]. Such phase separation of CHOL was described previously not only in the phospholipid membranes but also in the native SC and SC lipid model membranes [43,44].…”

Section: Evaluation Methodsmentioning

confidence: 99%

“…This peak position corresponds to a repeat distance of 33.6 ± 0.1 Å and was assigned to crystalline CHOL monohydrate [34]. The peak intensity increases with the increasing concentration of CHOL in the mixture, while the position is constant.…”

Section: Small-angle X-ray Diffraction From Mlvsmentioning

confidence: 99%

Influence of cholesterol on the structure of stratum corneum lipid model membrane

Zbytovská

Киселев

Funari³

et al. 2008

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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a b s t r a c tThis study describes the influence of cholesterol on a model membrane consisting of four stratum corneum (SC) lipids in three different states at 32 and 85 • C. Using small-angle X-ray diffraction on multilamellar vesicles, the lamellar repeat distance, D, was determined. Small-angle neutron scattering on unilamellar vesicles was used to calculate the membrane thickness, average area of the membrane surface per molecule, average volume per molecule in the membrane, and membrane density. After the sample preparation, the membranes show one lamellar phase. Over 10 days, the systems separate into two lamellar phases and crystalline cholesterol. On heating the samples to 85 • C, the domains merge into one phase, the D-value of which increases slightly with increasing cholesterol concentration. On cooling the samples back to 32 • C, only one phase is observable again. The increasing cholesterol concentration in the membrane causes a decrease in the D-value, membrane thickness, and membrane density. Simultaneously, the area of the membrane surface and membrane volume per molecule increase. In conclusion, cholesterol fluidises the SC lipid membranes in the state below the main phase transition and condenses above it. This effect can have an important impact on the pathologic skin states such as the recessive X-linked ichthyosis.

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Crystal structure of cholesterol monohydrate

Cited by 281 publications

References 7 publications

Pseudosymmetry in cholesterol monohydrate

Pseudosymmetry in cholesterol monohydrate

Structure of cholesterol helical ribbons and self-assembling biological springs

Influence of cholesterol on the structure of stratum corneum lipid model membrane

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