title: Interaction of Globular Plasma Proteins with Water-Soluble CdSe Quantum Dots.
abstract: The interactions between water-soluble semiconductor quantum dots [hydrophilic 3-mercaptopropionic acid (MPA)-coated CdSe] and three globular plasma proteins, namely, bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and human serum albumin (HSA), are investigated. Acidic residues of protein molecules form electrostatic interactions with these quantum dots (QDs). To determine the stoichiometry of proteins bound to QDs, we used dynamic light scattering (DLS) and zeta potential techniques. Fluorescence resonance energy transfer (FRET) experiments revealed energy transfer from tryptophan residues in the proteins to the QD particles. Quenching of the intrinsic fluorescence of protein molecules was noticed during this binding process (hierarchy HSA<β-Lg <BSA, lower binding affinity for hydrophobic protein molecules). Upon binding with QD particles, the protein molecules underwent substantial conformational changes at the secondary-structure level (50 % helicity lost), due to loss in hydration.
authors.affiliation: School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India).
authors.forename: Jyotsana
authors.initials: J
authors.lastname: Pathak
authors.affiliation: Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067 (India). kamla.jnu@gmail.com.|Inter University Accelerator Centre (IUAC), New Delhi 110067 (India). kamla.jnu@gmail.com.
authors.forename: Kamla
authors.initials: K
authors.lastname: Rawat
authors.affiliation: School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India).
authors.forename: Shilpa
authors.initials: S
authors.lastname: Sanwlani
authors.affiliation: Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067 (India). bohi0700@mail.jnu.ac.in.|School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India). bohi0700@mail.jnu.ac.in.
authors.forename: H B
authors.initials: HB
authors.lastname: Bohidar
mesh_terms: D001665:Binding Sites; D019187:Cadmium Compounds / Q000737:chemistry*; D005453:Fluorescence; D006801:Humans; D046529:Microscopy, Electron, Transmission; D045663:Quantum Dots / Q000737:chemistry / Q000378:metabolism*; D018036:Selenium Compounds / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D012709:Serum Albumin; D014867:Water; C058667:cadmium selenide
keywords: conformation analysis; hydration; proteins; quantum dots; secondary structure