tailieunhanh - Báo cáo khoa học: Kinetic characterization, structure modelling studies and crystallization of Trypanosoma brucei enolase

In this article, we report the results of an analysis of the glycolytic enzyme enolase (2-phospho-D-glycerate hydro-lase) of Trypanosoma brucei. Enolase activity was detected in both bloodstream-form and procyclic insect-stage try-panosomes, although a lower specific activity was found in the cultured procyclic homogenate. Subcellular localization analysis showed that the enzyme is only pre-sent in the cytosol. | Eur. J. Biochem. 270 3205-3213 2003 FEBS 2003 doi Kinetic characterization structure modelling studies and crystallization of Trypanosoma brucei enolase Veroniaue Hannaert1. Marie-Astrid Albert1 Daniel J. Riaden2. M. Theresa da Silva Giotto3 B Otavio Thiemann3 Richard C. Garratt3. Joris Van Rov1. Fred R. Oooerdoes1 and Paul A M. Michels1 B B bB B 1 Research Unit for Tropical Diseases Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry Universite Catholique de Louvain Brussels Belgium 2CENARGENjEMBRAPA . Brazil 3Instituto de Fisica de São Carlos Universidade de Sao Paulo São Carlos - SP Brazil In this article we report the results of an analysis of the glycolytic enzyme enolase 2-phospho-D-glycerate hydrolase of Trypanosoma brucei. Enolase activity was detected in both bloodstream-form and procyclic insect-stage trypanosomes although a lower specific activity was found in the cultured procyclic homogenate. Subcellular localization analysis showed that the enzyme is only present in the cytosol. The T. brucei enolase was expressed in Escherichia coli and purified to homogeneity. The kinetic properties of the bacterially expressed enzyme showed strong similarity to those values found for the natural T. brucei enolase present in a cytosolic cell fraction indicating a proper folding of the enzyme in E. coli. The kinetic properties of T. brucei enolase were also studied in comparison with enolase from rabbit muscle and Saccharomyces cerevisiae. Functionally similarities were found to exist between the three enzymes the Michaelis constant Km and KA values for the substrates and Mg2 are very similar. Differences in pH optima for activity inhibition by excess Mg2 and susceptibilities to monovalent ions showed that the T. brucei enolase behaves more like the yeast enzyme. Alignment of the amino acid sequences of T. brucei enolase and other eukaryotic and prokaryotic enolases showed that most .