Glycolipid Structure: The Complete Guide !

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Glycolipid structure can be found in cell membranes. Glycolipids are the type of non simple lipids which comprises carbohydrates, lipids including sphingolipids and fatty acids followed by a glycerol  group.

Glycolipids are made up of monosaccharide or oligosaccharide groups that are connected with sphingolipids or glycerol groups that are acetylated or alkylated by nature with one or two fatty acids. The article is a complete guide on the glycolipid structure, their location and purpose they serve. The article covers about the introduction to glycolipids, glycolipid structure with diagram, Synthesis of Glycolipid, location, types and function of the glycolipids.

What are glycolipids?

Glyco meaning one or many monosaccharide particle or compound that is attached with a glycosidic linkage

Glycolipids are the type of network of  lipids which consist  of carbohydrates, lipids which include sphingolipids and fatty acids followed by a glycerol  group.

The compounds are attached or linked with the glycosidic or covalent bond.

0303 Lipid Bilayer With Various Components 1
Glycolipids
Image credits- Wikimedia

Glycolipid structure

  • Glycolipids are made up of monosaccharide or oligosaccharide groups that are connected with sphingolipids or glycerol groups that are acetylated or alkylated by nature with one or two fatty acids.
  • Glycosphingolipids and glycoglycerolipids belong to these classes.
  • Hydrophobicity of the lipid tail of glycolipids enables them to bind to the lipid bilayer and anchor to the plasma membrane surface.

Synthesis of Glycolipid:     

  • The glycolipids are synthesized by adding sugars to the lipids sequentially through a series of enzymes.
  • Lactosylceramide (LacCer; Beta-D-galactosyl(1→ 4)-Beta-D-glucosyl-ceramide) is the first step in the synthesis of glycosphingolipids, where the first step is acylation and desaturation of D-erythro-sphinganine. 
  • In order to form lactosylceramide, ceramide is glucosylated and then Beta -galactosylated extracellularly. 
  • Glycosyltransferases and sulfotransferases can further elongate the chain. 
  • In plants, for example, a major glycoglycerolipid is synthesized by transferring a galactosyl from UDP-Gal to diacylglycerol via galactosyltransferases. 
  • Alpha-D-galactosyl-(1,6)-O-Beta-D-galactosyl diacylglycerol is formed by an additional galactosyl transfer from UDP-Gal

Glycolipid Diagram with explanation:

  • From the image shown below, we can observe the presence of the lipid membrane
  • The lipid molecules are present in the lipid membrane and they attached to each other with ester bond
glycolipid structure
Glycolipid Structure
  • To this, the carbohydrate molecule that is the sugar molecule or to be more explicit a monosaccharide is attached following many sugar molecules
  • So here the lipid is attached to a carbohydrate molecule or the sugar molecules
  • This is called the glycolipid structure
  • Gly– sugar molecule + lipid= glycolipid

Location of Glycolipid :

  • The glycolipids are found in the cellular membrane of the eukaryotic cells.
  • Glycolipids are present or can be found on the outer region or the so called leaflet of the cellular membrane in the eukaryotic cells

Types of Glycolipid :

  • With regard to the presence of the component of lipid, the glycolipids are grouped into 3 types.
  • Glycosphingolipids which are known as the GSLs, Glycoglycerolipids, glycosylphosphatidylinositols which are known as the GPIs.
  • The classes that form GLSs are cerebrosides and Gangliosides.
  • Brain and peripheral nervous tissue contain cerebralosides, which are glycolipids or glycosphingolipids.
  • Additionally, its role as an insulator also, cerebralosides also behaves as a protective coating or sheets for the cell in the nerve.
  • In post-translational modification, which actually happens after the process of translation, glycophosphatidylinositol, or the well known GPI, can be adhered to the C-terminus of a protein.
  • In a diversity (wide variety) of biological processes, GPI-anchored proteins play a vital role.
  • A glycolipid or glycosphingolipid is a type of ganglioside and contains a sialic acid residue.
  • Located abundantly in the neuron’s plasma membrane, ganglioside are the main components of the animal’s membrane.
  • A glycosphingolipid is a lipid found in the cell membrane (more specifically, a sphingolipid). They are made up of two parts: a hydrophobic ceramide component and a glycosidic carbohydrate component.
  • A glycoglycerolipid is composed of 1,2-di-O-acyl-sn-glycerols linked to a carbohydrate moiety by a glycosidic linkage.
  • Bacteria and plants produce glycoglycerolipids mainly as major glycolipids in photosynthetic tissues.

Functions of glycolipids:

  • Cells receive energy from glycolipids.
  • Glycolipids are an integral portion or a segment of cell membranes.
  • An individual’s blood group can be determined by glycolipids.
  • Red blood cells contain glycolipids that act as receptors.
  • By destroying and eliminating pathogens from the body, glycolipids also aid the immune system.

Summary:

Glycolipids are made up of monosaccharide or oligosaccharide groups that are connected with sphingolipids or glycerol groups that are acetylated or alkylated by nature with one or two fatty acids. They are present in the cell membrane of the eukaryotes.

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