Studies of the Interaction Between Ciprofloxacin and the Hemocyanin From Chinese Mitten Crab Eriocheir Japonica Sinensis

Abstract

The interactions between ciprofloxacin and hemocyanin were investigated by ultraviolet-vis absorbance, circular dichroism, and fluorescence spectra techniques. The ciprofloxacin effectively quenched the intrinsic fluorescence of hemocyanin via static quenching. There is only one class of binding site at the interface of hemocyanin. The hydrophobic and electrostatic interactions played a major role in the binding process of ciprofloxacin-hemocyanin system. The distance between the tryptophan residues and ciprofloxacin was calculated using Főrster theory to be 3.859 nm. The alteration of the environment of tryptophan residues and the secondary protein structure in the presence of the ciprofloxacin was confirmed by circular dichroism, synchronous, and three-dimensional fluorescence spectra.

Keywords:

• Ciprofloxacin
• Fluorescence spectra
• Hemocyanin
• Interaction

Acknowledgments

We gratefully acknowledge financial support of the Fund for Excellent Innovation Team of Jiangsu Provincial Department of Education (No. 2009-23), the National Natural Science Foundation of China (Project No. 30570218, 31071897), the Natural Science Foundation of Education Department of Jiangsu Province (Grant No. 07KJA18017), the Educational Bureau (Grant No.09KJD150007), the Jiangsu Fundament of “Qilan Project” and “333 Project,” and the Scientific Foundation of Yancheng Teachers University.

Notes

^a The correlation coefficient.

^b The standard deviation.

^a The correlation coefficient.

^b The standard deviation.