Lipid polymorphism

Lipid polymorphism

Polymorphism in biophysics is the aspect of the behaviour of lipids that influences their long-range order, i.e. how they aggregate. This can be in the form of spheres of lipid molecules (micelles), pairs of layers that face one another (lamellar phase, observed in biological system as a lipid bilayer), a tubular arrangement (hexagonal), or various cubic phases (Fd3m, Im3m, Ia3m, Pn3m, and Pm3m being those discovered so far). More complicated aggregations have also been observed, rhombohedral, tetragonal and orthorhombic phases have been observed.

It forms an important part of current academic research in the fields of membrane biophysics (polymorphism), biochemistry (biological impact) and organic chemistry (synthesis).

Determination of the topology of a lipid system is possible by a number of methods, the most reliable of which is x-ray diffraction. This uses a beam of x-rays that are scattered by the sample, giving a diffraction pattern as a set of rings. The ratio of the distances of these rings from the central point indicates which phase(s) are present.

The structural phase of the aggregation is influenced by the ratio of lipids present, temperature, hydration, pressure and ionic strength (and type).

ee also

*Lyotropic liquid crystal
*Amphiphile
*Critical micelle concentration

References

* J. M. Seddon, R. H. Templer. "Polymorphism of Lipid-Water Systems", from the Handbook of Biological Physics, Vol. 1, ed. R. Lipowsky, and E. Sackmann. (c) 1995, Elsevier Science B.V. ISBN 0-444-81975-4


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Polymorphism — or dimorphism may refer to: Contents 1 Biology 2 Computing 3 Chemistry …   Wikipedia

  • Lipid bilayer — [ phosphatidylcholine.] A lipid bilayer or bilayer lipid membrane (BLM) is a membrane composed of lipid molecules (usually phospholipids). The lipid bilayer is a critical component of all biological membranes, including cell membranes, and so is… …   Wikipedia

  • Lipid — Structures of some common lipids. At the top are oleic acid[1] and cholesterol.[2] The middle structure is a triglyceride composed of oleoyl, stearoyl, and palmitoyl chains at …   Wikipedia

  • Phospholipid — Phospholipids are a class of lipids and are a major component of all biological membranes. All phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline. TOC Amphipathic characterThe head of a… …   Wikipedia

  • Liquid crystal — Schlieren texture of liquid crystal nematic phase Liquid crystals (LCs) are a state of matter that have properties between those of a conventional liquid and those of a solid crystal.[1] For instance, an LC may flow like a liquid, but its… …   Wikipedia

  • Amphiphile — (from the Greek αμφις, amphis: both and φιλíα, philia: love, friendship) is a term describing a chemical compound possessing both hydrophilic and hydrophobic properties. Such a compound is called amphiphilic or amphipathic. This forms the basis… …   Wikipedia

  • Membrane biophysics — is the study of biological membranes using physical, computational, mathematical, and biophysical methods. See also Lipid polymorphism Lipid Amphiphile References Membrane Biophysics is the use of physical methods applied to cell membrane… …   Wikipedia

  • Hexagonal crystal system — In crystallography, the hexagonal is one of the 7 crystal system, it contains 7 point groups . It has the same symmetry as a right prism with a hexagonal base. There is only one hexagonal Bravais lattice, which has six atoms per unit… …   Wikipedia

  • Critical micelle concentration — In colloidal and surface chemistry, the critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and almost all additional surfactants added to the system go to micelles.[1] The CMC is an… …   Wikipedia

  • Pathophysiology of chronic fatigue syndrome — The pathogenesis of chronic fatigue syndrome (CFS) is uncertain, but may involve multiple organ and body systems, including neurological, endocrinal and immunological factors.Nervous system factorsNeurological abnormalitiesCFS may involve… …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”