PHYLOGENETIC ANALYSIS OF FATTY ACID DESATURASES REVEALS CONTRASTING EVOLUTIONARY CLUES IN CILIATES

MARIA LUZ SANCHEZ; CID NICOLAS; MONTES, GUADALUPE; EUGENIA ELGUERO; B.C. NUDEL; A. D. NUSBLAT

Cordoba

Congreso; - SAIB - 5 2 th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The Integral Membrane Diiron Enzymes (IMDE) are a class of binuclear non-heme iron proteins widely distributed amongprokaryotes and eukaryotes. They are characterized by a conserved tripartite motif consisting of eight to ten histidines. Their keyfunction is the activation of the dioxygen moiety to serve as efficient catalysts for reactions of hydroxylation, desaturation orreduction. To date most studies on IMDE were carried out in metazoan, phototrophic or parasitic organisms, whereas genome-wideanalysis in heterotrophic free living protozoa, such as the Ciliophora phylum, has not been undertaken. Our genome wide approachretrieved 91 putative sequences of the IMDE type with large differences in number among the ciliates: 7 in I. multifiliis, 13 in O.trifallax, 18 in S. lemnae, 24 in T. thermophila and 30 in P. tetraurelia. Interestingly, the analysis of the FA desaturases family showedthat the spirotrichs O. frifallax and S. lemnae have no genes that encode for any of these proteins, suggesting that their lipids derivefrom algae like C. reinhardtii, which is used as food in their cultures. Noteworthy the lipid content of O. frifallaxmeasured by GC?MSrevealed a quantitative composition in saturated and unsaturated fatty acids that was significantly different from the algae, thusindicating re-routing, modification and regulation of precursors not previously describe