title: Spectroscopic studies on the interaction between EcoRI and CdS QDs and conformation of EcoRI in EcoRI-CdS QDs bioconjugates.
abstract: Water-soluble fluorescent quantum dots (QDs) have been widely used in biological and biomedical fields, and the interaction between QDs and proteins and the conformational structure of the protein in the bioconjugate has attracted increasing attention. In this study, UV-Vis spectroscopy, fluorescence quenching, CD spectra, gel electrophoresis and Fourier transform infrared (FTIR) spectroscopic techniques were used to systematically investigate the interaction between type II restriction endonuclease (EcoRI) and CdS QDs and the conformational structure of EcoRI in the EcoRI-CdS QDs bioconjugates. The results indicated that electrostatic interactions played a major role in the binding reaction at pH 6.0, and the nature of quenching was static, resulting in forming CdS QDs-EcoRI bioconjugates. FTIR and CD spectra studies indicated a decrease of α-helical and turn structures accompanied by the increase of β-sheet structures of EcoRI in the bioconjugates. This study showed that the interaction between EcoRI and CdS QDs resulted in a change in the secondary structure of EcoRI after it was conjugated with CdS QDs, but the enzyme activity was maintained.
authors.affiliation: Key Laboratory of Functional Small Organic Molecules, Ministry of Education, Jiangxi Normal University, Nanchang 330022, People's Republic of China.
authors.forename: Yonghai
authors.initials: Y
authors.lastname: Song
authors.forename: Dan
authors.initials: D
authors.lastname: Luo
authors.forename: Shuhong
authors.initials: S
authors.lastname: Ye
authors.forename: Mei
authors.initials: M
authors.lastname: Huang
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhong
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Huang
authors.forename: Haoqing
authors.initials: H
authors.lastname: Hou
authors.forename: Li
authors.initials: L
authors.lastname: Wang
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D015246:Deoxyribonuclease EcoRI / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D011487:Protein Conformation; D045663:Quantum Dots; D013057:Spectrum Analysis; D013440:Sulfides / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D004800:Enzymes, Immobilized; D013440:Sulfides; C034939:cadmium sulfide; D015246:Deoxyribonuclease EcoRI