title: Metal ions-induced conformational change of P23 by using TNS as fluorescence probe.
abstract: In 10 mM N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (Hepes), pH 7.4, 25 degrees C, the conformational change of the truncated form of ciliate Euplotes Octocarinatus centrin (P23) induced by metal ions were investigated using 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as a probe. The results show that upon metal ions binding, P23 undergo a conformational change and the contributions to the conformational change from the two EF-hands are different, and Tb3+ has more larger influence than Ca2+ with the same concentration metal ions, which provide possible the evidence that the different EF-hands play distinct biological functions. Meanwhile, the conditional binding constants of TNS and Ca2-loaded or Tb2-loaded P23 were obtained, K (Ca2-P23+TNS)=(7.49+/-0.88)x10(5) mol-1 L, K (Tb2-P23+TNS)=(8.24+/-0.49)x10(5) mol-1 L.
authors.affiliation: Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Lie-Xiang
authors.initials: LX
authors.lastname: Ren
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Zhao
authors.forename: Guo-Ting
authors.initials: GT
authors.lastname: Li
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Liang
authors.forename: Bin-Sheng
authors.initials: BS
authors.lastname: Yang
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D016812:Euplotes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000378:metabolism*; D007700:Kinetics; D009282:Naphthalenesulfonates / Q000378:metabolism*; D011487:Protein Conformation / Q000187:drug effects; D015800:Protozoan Proteins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013725:Terbium / Q000494:pharmacology*; D017186:Titrimetry
chemical_list: D005456:Fluorescent Dyes; D009282:Naphthalenesulfonates; D015800:Protozoan Proteins; D013725:Terbium; C009497:2-(4-toluidino)-6-naphthalenesulfonic acid; D002118:Calcium