Glycolipids Occurrence, Significance, and Properties

Structural Biochemistry, Research Center Borstel, 23485 Borstel, Germany oholst fz-borstel.de 

This chapter focuses on the occurrence and the physicochemical properties of glycolipids in Nature. Owing to space limitations, the presented overview must be incomplete, and, thus, mainly publications of the past 15 years are included. However, all review articles cited herein inform the interested reader about earlier work. Although lipopolysaccharides (LPS), lipoara-binomannan (LAM), lipomannan, lipoglycans, and lipoteichoic acids are not understood as glycolipids per definition, their occurrence and properties are also described in this chapter. GPI-anchored lipids is a main topic ofO Chap. 7.4. 

In cells, a particular composition and the physicochemical properties of the lipid matrix at given ambient conditions represent the basis for a normal functioning [3]. Any disturbance of the composition due, e. g., to different net charges or acylation patterns may result in changes of membrane fluidity/permeability, in phase separation, or in disruption of the lamellar membrane architecture. However, cells are potentially able to overcome such changes in lipid matrix composition by altering it ( homovicious adaptation ) [4]. If an adaptation of this type does not take place, severe dysfunction of a cell may occur. 

Various means and methodologies have been used to investigate the physicochemical properties of synthetic, semisynthetic, and natural glycolipids, e. g., NMR spectroscopy. X-ray diffraction, electron microscopy, or Fourier-transformed infrared spectroscopy (FTIR). In the following paragraphs, the occurence and physicochemical properties of different biological glycolipid classes and of lipopolysaccharides, lipoteichoic acids, and mycobacterial mycolates are briefly discussed. 

Sulfoglycodialkylglycerolipids from the halobacteiia, (a) Natralba asiatica, and (b) Halobacterium salinarum and Hb. saccharovorum. ff=SO r 

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