tailieunhanh - Báo cáo khoa học: Functional characterization of front-end desaturases from trypanosomatids depicts the first polyunsaturated fatty acid biosynthetic pathway from a parasitic protozoan

A survey of the three kinetoplastid genome projects revealed the presence of three putative front-end desaturase genes inLeishmania major, one in Trypanosoma bruceiand two highly identical ones (98%) inT. cruzi. The encoded gene products were tentatively annotated as D8, D5 and D6 desaturases for L. major, and D6 desaturase for both trypanosomes. | ềFEBS Journal Functional characterization of front-end desaturases from trypanosomatids depicts the first polyunsaturated fatty acid biosynthetic pathway from a parasitic protozoan Karina E. J. Tripodi Laura V. Buttigliero Silvia G. Altabe and Antonio D. Uttaro Institute de Biologia Molecular y Celular de Rosario IBR CONICET Departamento de Microbiologia Facultad de Ciencias Bioquimicas y Farmaceuticas Universidad Nacionalde Rosario Santa Fe Argentina Keywords front-end desaturases Leishmania lipids Trypanosoma trypanosomatids Correspondence A. D. Uttaro IBR-CONICET Dpto Microbiologia Facultad de Ciencias Bioquimicas y Farmaceuticas Universidad Nacionalde Rosario Suipacha 531 2000 Rosario Santa Fe Argentina Fax 54 341 4390465 Tel 54 341 4350661 E-mail toniuttaro@ Received 30 September 2005 revised 28 October 2005 accepted 3 November 2005 doi A survey of the three kinetoplastid genome projects revealed the presence of three putative front-end desaturase genes in Leishmania major one in Trypanosoma brucei and two highly identical ones 98 in T. cruzi. The encoded gene products were tentatively annotated as D8 D5 and D6 desaturases for L. major and D6 desaturase for both trypanosomes. After phylogenetic and structural analysis of the deduced proteins we predicted that the putative D6 desaturases could have D4 desaturase activity based mainly on the conserved HX3HH motif for the second histidine box when compared with D4 desaturases from Thraustochy-trium Euglena gracilis and the microalga Pavlova lutheri which are more than 30 identical to the trypanosomatid enzymes. After cloning and expression in Saccharomyces cerevisiae it was possible to functionally characterize each of the front-end desaturases present in L. major and T. brucei. Our prediction about the presence of D4 desaturase activity in the three kinetoplastids was corroborated. In the same way D5 desaturase activity was confirmed to be present in L. major. .