High level expression and thermal characterization of human centrin 1

Human centrin 1 (Hcen 1) is an acidic calcium binding protein with a molecular mass of ∼20 kDa and has been localized in human as well as in mouse testis, at the base of the flagellar apparatus in sperm cells. Its putative function is associated with the fertilized zygote duplication and motility of the sperm. In an effort to provide a better understanding of the Hcen 1 structure, high level expression and protein purification, using affinity and anion exchange chromatography, were performed. A successful expression was obtained with optical density measures of 9 and an average of 40 grams of bacterial pellet, which leads to 10 mg of ∼99% pure Hcen 1. Differential Scanning Calorimetry studies were done using the purified Hcen 1, obtaining two pre-transitional peaks at ∼58.42°C and ∼88.82°C. These results suggest that Hcen 1 undergoes conformational changes related with its N- and C-terminal calcium binding capacities.