The Properties Analysis Of Human Centrin 1

Centrins are small,acidic Ca²⁺ binding proteins of the EF-hand superfamily,centrins were first identified in unicellular green algae,as components of the basal bodies-associated,in many eukaryotes,centrins have also been discovered,including higher plants,yeast,invertebrates and humans.In the process of different cells,plays an important role.There are four human centrin isoforms: centrin1,centrin2,centrin3 and the pseudogene centrin4?for short HsCen1-HsCen4,respectively?.All four isoforms have been associated with the interconnecting cilia within the retina and have been associated with visual signal transduction.But the four centrin have different functions,so may have different biological significance,based on the research,on the basis of HsCen2 further studied the following properties of HsCen1:First,we studied HsCen1 before and after phosphorylation combination of Tb³⁺ and Ca²⁺,the reaction of Ca²⁺ and HsCen1 is exothermic,enthalpy driver response;the reaction of Tb³⁺and HsCen1 is endothermic,entropy driven reaction;per mole HsCen1 can combine 4 mole Tb³⁺,with the order of ? > ? > ? > ?.HsCen1 phosphorylated weakened binding constant of Ca²⁺ and Tb³⁺ with HsCen1.After HsCen1 combined with metal ions,HsCen1 conformational changed.HsCen1 phosphorylated conformational changes weaken.Then,we studied HsCen1 aggregation and its influencing factors by resonance light scattering spectrometry,the results show that metal ions can induce HsCen1 assembly,and Tb³⁺caused assemble much stronger than the Ca²⁺.The concentration of HsCen1,rare earth metal ion and ionic strength and TNS all can affect HsCen1 aggregation: HsCen1 aggregation degree was positively correlated with the concentration of the protein itself;with the increase of the radius of metal ion,Tb³⁺ caused HsCen1 assemble reduced;with the increase of KCl salt concentration,Tb³⁺ caused HsCen1 gathered reduced;with the increase of TNS and HsCen1 proportion,Tb³⁺cause HsCen1 gathered weakened.After HsCen1 phosphorylation,HsCen1 aggregation degree reduced,HsCen1 assembly may regulated by the hydrophobic effect and electrostatic interactions.Finally,study the interaction of HsCen1 before and after phosphorylation with R18-Sfi1,the results showed that reaction is enthalpy driven,exothermic reaction;per mole HsCen1 can combine 1 mole R18-Sfi1,independent of calcium ions,but the presence of calcium ions,enhanced the interaction between them.but,after HsCen1 phosphorylation,must rely on calcium ions can be combined with R18-Sfi1,and phosphorylation,weakened the affinity between them.