Inhibition Of Functions For C-Terminal Domain Of Euplotes Octocarinatus Centrin By Chlorpromazine Hydrochloride

The binding of chlorpromazine (CPZ) to the C-terminal domain of Euplotes octocarinatus centrin ( apoC-EoCen) and the effect of CPZ on the protein function were studied by fluorescence spectra, isothermal titration calorimetry (ITC), circular dichroism (CD) and electrophoresis. The results illustrated that in 10 mmol.L-1 Hepes solution (pH=7.4) at room temperature, CPZ and apoC-EoCen were combined with a molar ratio of 1:1, in addition, the conditional binding constant was about 10(4) L.mol(-1). The combination of CPZ leads to changes in the secondary structure of the protein, and the content of a-helix is reduced. It inhibits the aggregation of centrin induced by metal ions and reduces the fluorescence intensity of Tb3+ sensitization. CPZ suppresses the binding of centrin to xeroderma pigmentosum protein (XPC). The activity of apoC-EoCen nuclease is affected, which results in the decreased capability of protein to cut pBR322 DNA. The results indicate that chlorpromazine hydrochloride is a biological function antagonist of centrin, and it has a good regulatory effect on the function of centrin.