title: Dynamic light-scattering analysis of the electrostatic interaction of hexahistidine-tagged cytochrome P450 enzyme with semiconductor quantum dots.
abstract: Currently, there is great interest in the development of methods suitable for determining the stoichiometry of biomolecules attached to nanoparticles. We describe the use of the dynamic light-scattering technique (DLS) to determine the stoichiometry of the protein cytochrome P450(BSbeta) attached to CdS and CdSe quantum dots (QDs). The enzyme-conjugated QDs have different diffusion characteristics compared to the QD and enzyme precursors, expressed in their size, scattering intensity as well as zeta-potential values. The significant enhancement of the scattering intensity of QDs observed upon conjugation with the P450(BSbeta) due to the refractive-index increment and the systematic variation in zeta potential resulting from charge neutralization of the anionic QDs by the cationic histidine-tagged P450(BSbeta) have been used for stoichiometry determination.
authors.affiliation: Biologisch-Chemische Mikrostrukturtechnik, Fachbereich Chemie, Universität Dortmund, Otto-Hahn Str. 6, 44227 Dortmund, Germany.
authors.forename: Binil Itty
authors.initials: BI
authors.lastname: Ipe
authors.forename: Anuj
authors.initials: A
authors.lastname: Shukla
authors.forename: Huachang
authors.initials: H
authors.lastname: Lu
authors.forename: Bo
authors.initials: B
authors.lastname: Zou
authors.forename: Heinz
authors.initials: H
authors.lastname: Rehage
authors.forename: Christof M
authors.initials: CM
authors.lastname: Niemeyer
mesh_terms: D000838:Anions; D001703:Biophysics / Q000379:methods*; D002412:Cations; D002627:Chemistry, Physical / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D004798:Enzymes / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006639:Histidine / Q000737:chemistry*; D008027:Light; D008968:Molecular Conformation; D009842:Oligopeptides / Q000737:chemistry*; D045663:Quantum Dots; D012542:Scattering, Radiation; D012666:Semiconductors; D055672:Static Electricity
chemical_list: D000838:Anions; D002412:Cations; D004798:Enzymes; C471213:His-His-His-His-His-His; D009842:Oligopeptides; D006639:Histidine; D003577:Cytochrome P-450 Enzyme System