Phosphatidylglycerol

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General chemical structure of a phosphatidyl glycerol where R1 and R2 are fatty acid side chains

Phosphatidylglycerol is a glycerophospholipid found in pulmonary surfactant.[1]

The general structure of phosphatidylglycerol consists of a L-glycerol 3-phosphate backbone ester-bonded to either saturated or unsaturated fatty acids on carbons 1 and 2. The head group substituent glycerol is bonded through a phosphomonoester. It is the precursor of surfactant and its presence (>0.3) in the amniotic fluid of the newborn indicates fetal lung maturity.

Approximately 98% of alveolar wall surface area is due to the presence of type I cells, with type II cells producing pulmonary surfactant covering around 2% of the alveolar walls. Once surfactant is secreted by the type II cells, it must be spread over the remaining type I cellular surface area. Phosphatidylglycerol is thought to be important in spreading of surfactant over the Type I cellular surface area. The major surfactant deficiency in premature infants relates to the lack of phosphatidylglycerol, even though it comprises less than 5% of pulmonary surfactant phospholipids. It is synthesized by head group exchange of a phosphatidylcholine enriched phospholipid using the enzyme phospholipase D.

Biosynthesis[edit]

Biosynthesis of Phophatidylglycerol

L-Glycerol-3-phosphate is activated by a CTP and pyrophosphate is cleaved off resulting in CDP-diglycerol. Glycerol-3-phosphate is attached to CDP-diglycerol and phosphatidylglycerol phosphate is formed, while CMP is released. The phosphate group is hydrolysed forming phosphatidylglycerol.

Two phosphatidylglycerols form cardiolipin, the constituent molecule of the mitochondrial inner membrane.[2]

See also[edit]

References[edit]

  1. ^ Richard J. King, Mary Catherine MacBeth (6 October 1981). "Interaction of the lipid and protein components of pulmonarysurfactant Role of phosphatidylglycerol and calcium". Biochimica et Biophysica Acta (BBA) - Biomembranes 647: 159–168. doi:10.1016/0005-2736(81)90242-X. 
  2. ^ Ying-Ying Chang and Eugene P. Kennedy (September 1967). "Biosynthesis of phosphatidyl glycerophosphate in Escherichia coli". The Journal of Lipid Research 8 (5): 447–455. 

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