title: Conformation, thermodynamics and stoichiometry of HSA adsorbed to colloidal CdSe/ZnS quantum dots.
abstract: Water-soluble luminescent colloidal quantum dots (QDs) have attracted great attention in biological and medical applications. In particular, for any potential in vivo application, the interaction of QDs with human serum albumin (HSA) is crucial. As a step toward the elucidation of the fate of QDs introduced to organism, the interactions between QDs and HSA were systematically investigated by various spectroscopic techniques under the physiological conditions. It was proved that binding of QDs and HSA is a result of the formation of QDs-HSA complex and electrostatic interactions play a major role in stabilizing the complex. The modified Stern-Volmer quenching constant K(a) at different temperatures and corresponding thermodynamic parameters DeltaH, DeltaG and DeltaS were calculated. Furthermore, the site marker competitive experiments revealed that the binding location of QDs with HSA is around site I, centered at Lys199. The conformational changes of HSA induced by QDs have been analyzed by means of CD and FT-IR. The results suggested that HSA underwent substantial conformational changes at both secondary and tertiary structure levels. The stoichiometry of HSA attached to QDs was obtained by dynamic light scattering (DLS) and zeta-potential.
authors.affiliation: State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiao
authors.forename: Shan
authors.initials: S
authors.lastname: Huang
authors.forename: Zu-De
authors.initials: ZD
authors.lastname: Qi
authors.forename: Bo
authors.initials: B
authors.lastname: Zhou
authors.forename: Zhi-Ke
authors.initials: ZK
authors.lastname: He
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001665:Binding Sites; D019187:Cadmium Compounds / Q000737:chemistry*; D003102:Colloids; D004735:Energy Transfer; D006801:Humans; D011487:Protein Conformation; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013440:Sulfides / Q000737:chemistry*; D013816:Thermodynamics; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D003102:Colloids; D018036:Selenium Compounds; D012709:Serum Albumin; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide