The Aggregation And Phosphorylation Of Euplotes Octocarinatus Centrin

Centrin holds two major functions, which are signal and aggregation. In organisms, the processes of signal transduction was regulated by the reversible phosphorylation of centrin. Furthermore, the aggregation of centrin has a large effect on the motor behavior. In this paper, the Ciliate Euplotes octocarinatus centrin (EoCen) was used to study the relationship of protein aggregation and phosphorylation.Firstly, the relationship between aggregation and phosphorylation of EoCen was explored primarily. The Resonance Light Scattering (RLS) experiments suggested that phosphorylated EoCen can aggregate and the degree of aggregation was smaller than that of centrin (EoCen). In addition, the degree of aggregation increased with the increasing of the concentration of protein.31P-NMR indicated that EoCen was phosphorylated with phosphorylated kinase (PKA) whether or not the EoCen was aggregated.Secondly, the effect of metal ions on EoCenp aggregation was investigated. RLS suggested that the binding of Tb3+to EoCen induced the EoCen aggregation. The degree of EoCen aggregation was various under different concentration of Tb3+. TNS was a fluorescent probe, which showed that the major force which inducing the EoCen aggregation was hydrophobic force. Moreover, RLS dynamic experiments suggested that the rate and degree of EoCenp aggregation induced by Tb3+was reduced comparing with EoCen. The result further clarified that the protein aggregated in the manner of side by side of N-N, C-C. The fluorescence lifetime manifested that the conformation of EoCen or the environment of Tyr was changed because of the aggregation of EoCen, which result in the lower fluorescence lifetime of EoCen.Finally, the effects of ionic strength and temperature on EoCenp aggregation were studied. The experimental results indicated that the increasing ionic strength and reducing of the temperature would inhibit the aggregation of EoCen. In addition, the inhibition degree influenced by ionic strength and temperature was decreased after protein phosphorylation.