Teichoic acids are bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l polysaccharides of glycerol phosphate or ribitol phosphate linked via phosphodiester bonds.

Location and structure

Teichoic acids are found within the cell wall

Cell wall

The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...

 of Gram-positive

Gram-positive

Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...

 bacteria such as species in the genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Staphylococcus

Staphylococcus

Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....

, Streptococcus

Streptococcus

Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...

, Bacillus

Bacillus

Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...

, Clostridium

Clostridium

Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...

, Corynebacterium

Corynebacterium

Corynebacterium is a genus of Gram-positive rod-shaped bacteria. They are widely distributed in nature and are mostly innocuous. Some are useful in industrial settings such as C. glutamicum. Others can cause human disease. C...

and Listeria, and appear to extend to the surface of the peptidoglycan

Peptidoglycan

Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of bacteria , forming the cell wall. The sugar component consists of alternating residues of β- linked N-acetylglucosamine and N-acetylmuramic acid...

 layer. Teichoic acids are not found in Gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

 bacteria. They can be covalently linked to N-acetylmuramic acid

N-Acetylmuramic acid

N-Acetylmuramic acid, or MurNAc, is the ether of lactic acid and N-acetylglucosamine with a chemical formula of C11H19NO8. It is part of a biopolymer in the bacterial cell wall, built from alternating units of N-acetylglucosamine and N-acetylmuramic acid , cross-linked with oligopeptides at the...

 of the peptidoglycan layer, to the lipids of the cytoplasmic membrane, or to a terminal D-alanine

Alanine

Alanine is an α-amino acid with the chemical formula CH3CHCOOH. The L-isomer is one of the 20 amino acids encoded by the genetic code. Its codons are GCU, GCC, GCA, and GCG. It is classified as a nonpolar amino acid...

 in the tetrapeptide

Tetrapeptide

A tetrapeptide is a peptide consisting of four amino acids joined by peptide bonds. Many tetrapeptides are pharmacologically active, often showing affinity and specificity for a variety of receptors in protein-protein signaling...

 crosslinkage between N-acetylmuramic acid units. The combination of teichoic acids and lipids are referred to as lipoteichoic acid

Lipoteichoic acid

Lipoteichoic acid is a major constituent of the cell wall of Gram-positive bacteria. These organisms have an inner membrane and, external to it, a thick peptidoglycan layer. It consists of teichoic acids, long chains of ribitol phosphate and is anchored to the lipid bilayer via a glyceride...

s.

Function

The main function of teichoic acids is to provide rigidity to the cell-wall by attracting cations such as magnesium and sodium. Teichoic acids are usually, but not always, substituted with D-alanine ester residues, giving the molecule zwitterion

Zwitterion

In chemistry, a zwitterion is a neutral molecule with a positive and a negative electrical charge at different locations within that molecule. Zwitterions are sometimes also called inner salts.-Examples:...

ic properties. These zwitterionic teichoic acids are suspected ligands for toll-like receptor

Toll-like receptor

Toll-like receptors are a class of proteins that play a key role in the innate immune system. They are single, membrane-spanning, non-catalytic receptors that recognize structurally conserved molecules derived from microbes...

s 2 and 4. Teichoic acids also assist in regulation of cell growth by limiting the ability of autolysins to break the β(1-4) bond between the N-acetyl glucosamine and the N-acetylmuramic acid.

Lipoteichoic acids also act as receptor molecules for some Gram-positive bacteriophage. Evidence suggests teichoic acid may act as a bacteriophage receptor; however, this has not yet been conclusively proven.

Lysis of Gram-positive bacteria and release of the teichoic acid into the bloodstream may cause fever, blood vessel dilation and possibly shock and subsequent death. Teichoic acid can also be used by bacteria to attach to mucosal membranes.

See also

• Lipoteichoic acid
  Lipoteichoic acid
  Lipoteichoic acid is a major constituent of the cell wall of Gram-positive bacteria. These organisms have an inner membrane and, external to it, a thick peptidoglycan layer. It consists of teichoic acids, long chains of ribitol phosphate and is anchored to the lipid bilayer via a glyceride...
  
   - a major constituent of the cell wall
  Cell wall
  The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...
  
   of gram-positive
  Gram-positive
  Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
  
  bacteria