title: Δ9 desaturase from Trypanosoma cruzi: Key enzyme in the parasite metabolism. Cloning and overexpression.
abstract: Desaturases, key enzymes in the metabolism of fatty acids, regulate the physical and biochemical properties of membranes. They adjust the composition of saturated and unsaturated fatty acids in response to changes in the environmental. We demonstrated the existence of Δ9 desaturase activity in epimastigotes of the Trypanosoma cruzi Tulahuen strain. In the present study, showed that this enzyme has an approximate molecular mass of 50kDa and a pI value of approximately 9. In order to characterize the Δ9 desaturase of Trypanosoma cruzi, (TcΔ9DES) we have cloned, sequenced and expressed in Escherichia coli. The gene consists of 1300bp and encodes a peptide of 433 amino acids with a molecular weight of 50kDa. Analysis of the amino acid sequence revealed three clusters of histidine and two hydrophobic regions, characteristic of membrane-bound desaturases. Gene expression studies showed that TcΔ9DES was overexpressed as an active protein. Fatty acid analysis showed that the expressed protein was confirmed to be functional with Δ9 desaturase activity. This enzyme changed the fatty acid profile of TcΔ9DES-expressing E. coli, decreasing the levels of palmitic (16:0) and stearic (18:0) acids and enhancing palmitoleic (16:1Δ9) and monounsaturated 18 carbons fatty acids. When [1-14C]palmitic or [1-14C]stearic acid was used as substrate, TcΔ9DES-expressing E. coli exhibited high desaturase activity associated with increased levels of monounsaturated fatty acids, suggesting that the TcΔ9DES enzyme was actively expressed in E. coli. To check the commitment of TcΔ9DES against sterol biosynthesis inhibitors we tested the activity under ketoconazole effect. Native TcΔ9DES, showed a significant activity inhibition. Since TcΔ9DES has shown active participation under different environmental factors, among them, ketoconazole, we consider that it plays a critical role in the metabolism of the parasite.
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina.
authors.forename: Mariela R
authors.initials: MR
authors.lastname: Woelke
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina.
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Paulucci
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina.
authors.forename: Armentano
authors.initials: A
authors.lastname: Selva
authors.affiliation: Department of Medicine, Division of Dermatology and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California, Los Angeles (UCLA), Los Angeles, CA, United States.
authors.forename: Hermes
authors.initials: H
authors.lastname: Garban
authors.affiliation: Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina. Electronic address: mgarcia@exa.unrc.edu.ar.
authors.forename: Mirta García
authors.initials: MG
authors.lastname: de Lema
mesh_terms: D001483:Base Sequence; D002849:Chromatography, Gas; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D015870:Gene Expression; D007525:Isoelectric Focusing / Q000379:methods; D007654:Ketoconazole / Q000494:pharmacology; D017421:Sequence Analysis; D013230:Stearoyl-CoA Desaturase; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism
chemical_list: D016054:DNA, Protozoan; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; C029627:delta-9 fatty acid desaturase; D007654:Ketoconazole
keywords: Desaturase gene; Heterologous expression; Ketoconazole; Trypanosoma cruzi; Unsaturated fatty acids; Δ9 desaturase