title: Protein translation elongation factor-1 alpha from Trypanosoma brucei binds calmodulin.
abstract: The following study examines the calmodulin (CaM) branch of the calcium signal pathway in the protozoan parasite Trypanosoma brucei. To accomplish this goal, a subset of cytosolic CaM-binding proteins (CaMBPs) was partially purified by a combination of DE52 and CaM-Sepharose affinity chromatography. Monoclonal antibodies (CBP-KK1) were used to clone the cDNA for a 53-kDa CaMBP from a lambda ZAP expression library of the metacyclic stage of T. brucei. The deduced amino acid sequence of clone CaMBP-12B had 81% overall amino acid identity to the translation elongation factor-1 alpha (EF-1 alpha) from Euglena gracilis and 76% identity to the rabbit EF-1 alpha. Rabbit EF-1 alpha was recognized by CBP-KK1 and was shown to bind to CaM-Sepharose in a calcium-dependent manner. By contrast, the complex of EF-1 alpha beta gamma did not bind CaM-Sepharose. A heterobifunctional sulfhydryl derivative of CaM (N-succinimidyl 3-(2-pyridyldithio)propionate-CaM) formed reducible cross-links with EF-1 alpha in solution but not with the complex of EF-1 alpha beta gamma. Biotinylated CaM bound weakly to trypanosome and rabbit EF-1 alpha in a gel overlay assay. This report demonstrates the direct interaction between CaM and the translation elongation factor EF-1 alpha.
authors.affiliation: Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275.
authors.forename: K J
authors.initials: KJ
authors.lastname: Kaur
authors.forename: L
authors.initials: L
authors.lastname: Ruben
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000302:isolation & purification; D002417:Cattle; D002846:Chromatography, Affinity; D016054:DNA, Protozoan; D004591:Electrophoresis, Polyacrylamide Gel; D005056:Euglena gracilis; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000378:metabolism*
chemical_list: D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D016054:DNA, Protozoan; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors