Fatty Acid Biosynthesis in Chromerids

• Published in: Biomolecules (Basel, Switzerland) Switzerland), 2020-07, Vol.10 (8), p.1102
• Main Authors: Tomčala, Aleš, Michálek, Jan, Schneedorferová, Ivana, Füssy, Zoltán, Gruber, Ansgar, Vancová, Marie, Oborník, Miroslav
• Format: Article
• Language: English
• Subjects: Algae; Animals; Apicomplexa - classification; Apicomplexa - genetics; Apicomplexa - metabolism; Biosynthesis; Biosynthetic Pathways - genetics; Chromatography; Chromera velia; Cytosol; de novo biosynthesis; elongation; Endoplasmic reticulum; Enzymes; evolution; Evolution, Molecular; Fatty Acid Desaturases - classification; Fatty Acid Desaturases - genetics; Fatty Acid Desaturases - metabolism; Fatty Acid Elongases - classification; Fatty Acid Elongases - genetics; Fatty Acid Elongases - metabolism; Fatty Acid Synthase, Type I - classification; Fatty Acid Synthase, Type I - genetics; Fatty Acid Synthase, Type I - metabolism; Fatty Acid Synthase, Type II - classification; Fatty Acid Synthase, Type II - genetics; Fatty Acid Synthase, Type II - metabolism; Fatty acids; Fatty Acids - biosynthesis; Genomes; Humans; Life cycles; Lipids; Livestock; Maximum likelihood method; Metabolomics; Parasites; Phylogenetics; Phylogeny; Protozoa; Protozoan Infections - parasitology; Protozoan Proteins - classification; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Species Specificity; Transmission electron microscopy; Vitrella brassicaformis
• ISSN: 2218-273X; 2218-273X
• DOI: 10.3390/biom10081102

Fatty acids are essential components of biological membranes, important for the maintenance of cellular structures, especially in organisms with complex life cycles like protozoan parasites. Apicomplexans are obligate parasites responsible for various deadly diseases of humans and livestock. We analyzed the fatty acids produced by the closest phototrophic relatives of parasitic apicomplexans, the chromerids and , and investigated the genes coding for enzymes involved in fatty acids biosynthesis in chromerids, in comparison to their parasitic relatives. Based on evidence from genomic and metabolomic data, we propose a model of fatty acid synthesis in chromerids: the plastid-localized FAS-II pathway is responsible for the de novo synthesis of fatty acids reaching the maximum length of 18 carbon units. Short saturated fatty acids (C14:0-C18:0) originate from the plastid are then elongated and desaturated in the cytosol and the endoplasmic reticulum. We identified giant FAS I-like multi-modular enzymes in both chromerids, which seem to be involved in polyketide synthesis and fatty acid elongation. This full-scale description of the biosynthesis of fatty acids and their derivatives provides important insights into the reductive evolutionary transition of a phototropic algal ancestor to obligate parasites.