Acyl-CoA: lysophosphatidylcholine acyltransferase from diatom P. Tricornutum efficiently remodels phosphatidylcholine containing polyunsaturated fatty acids.

This study presents characterisation of diatom's PtLPCAT1 (acyl-CoA: lysophosphatidylcholine acyltransferase) activity in phospholipid remodelling. In this research microsomal fractions of yeast Δale1 mutant overexpressing PtLPCAT1 were used as a source of the tested enzyme. In the assays evaluating remodelling of different phospholipids by PtLPCAT1 not modified microsomal fractions of the tested yeast were used.

Two plastidial lysophosphatidic acid acyltransferases differentially mediate the biosynthesis of membrane lipids and triacylglycerols in Phaeodactylum tricornutum.

Lysophosphatidic acid acyltransferases (LPAATs) catalyze the formation of phosphatidic acid (PA), a central metabolite in both prokaryotic and eukaryotic organisms for glycerolipid biosynthesis. Phaeodactylum tricornutum contains at least two plastid-localized LPAATs (ptATS2a and ptATS2b), but their roles in lipid synthesis remain unknown. Both ptATS2a and ptATS2b could complement the high temperature sensitivity of the bacterial plsC mutant deficient in LPAAT.

Diatoms and Plants Acyl-CoA:lysophosphatidylcholine Acyltransferases (LPCATs) Exhibit Diverse Substrate Specificity and Biochemical Properties.

The search of the genome database revealed the existence of six genes potentially encoding lysophospholipid acyltransferases. One of these genes, Phatr3_J20460, after introduction to yeast mutant disrupted in the LPCAT gene, produced a very active acyl-CoA:lysophosphatidylcholine (LPCAT) enzyme. Using in vitro assays applying different radioactive and non-radioactive substrates and microsomal fractions from such yeast, we have characterized the biochemical properties and substrate specificities of this LPCAT1.