Characterization of melittin binding to Euplotes octocarinatus centrin

Yaqin Zhao; Jiuying Feng; Zhijun Wang; Aihua Liang; Binsheng Yang

doi:10.1016/j.saa.2007.10.003

Characterization of melittin binding to Euplotes octocarinatus centrin

Spectrochim Acta A Mol Biomol Spectrosc. 2008 Sep;70(4):884-7. doi: 10.1016/j.saa.2007.10.003. Epub 2007 Oct 9.

Authors

Yaqin Zhao¹, Jiuying Feng, Zhijun Wang, Aihua Liang, Binsheng Yang

Affiliation

¹ Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.

PMID: 18054274
DOI: 10.1016/j.saa.2007.10.003

Abstract

In the presence of 1.0mM Ca2+, the interaction between Euplotes octocarinatus centrin (EoCen) and melittin (ME) was studied by means of fluorescence spectra. In 0.1M N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (Hepes) and 150mM NaCl at pH 7.4, fluorescence peak of ME was observed at about 353nm indicating that micro-environment of Tryptophan (Trp) residue in ME was hydrophilic. With the addition of 3.2x10(-4)M calcium saturated EoCen (holoEoCen), the peak of ME was blue-shifted to 339nm, which may be resulted from micro-environmental changes of the peptide. At the same time, fluorescence emission of ME was increased significantly suggesting that new complex of ME-holoEoCen was formed under the experimental conditions. Based on the fluorescence titration curves, the 1:1 stoichiometric ratio of holoEoCen to ME was confirmed. In addition, the conditional binding constant of holoEoCen with ME was calculated to be logKME-holoEoCen=6.59+/-0.14.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Animals
Calcium-Binding Proteins / chemistry*
Calcium-Binding Proteins / metabolism
Euplotes / chemistry*
Melitten / chemistry*
Melitten / metabolism
Molecular Sequence Data
Protein Binding
Spectrophotometry
Titrimetry

Substances

Calcium-Binding Proteins
Melitten