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 λZAP 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-1α (EF-1α) from Euglena gracilis and 76% identity to the rabbit EF-1α. Rabbit EF-1α was recognized by CBP-KK1 and was shown to bind to CaM-Sepharose in a calcium-dependent manner. By contrast, the complex of EF-1αβγ did not bind CaM-Sepharose. A heterobifunctional sulfhydryl derivative of CaM (N-succinimydyl 3-(2- pyridyldithio)propionate-CaM) formed reducible cross-links with EF-1α in solution but not with the complex of EF-1αβγ. Biotinylated CaM bound weakly to trypanosome and rabbit EF-1α in a gel overlay assay. This report demonstrates the direct interaction between CaM and the translation elongation factor EF-1α.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - Sep 16 1994|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology