title: Supramolecular Recognition Induces Nonsynchronous Change of Dye Fluorescence Properties.
abstract: Fluorescence behavior of 8-anilino-1-naphthalenesulfonate (ANS) reflects a blue-shift and fluorescence enhancement on decreasing solvent polarity, with both properties affected in a synchronous way in solvent mixtures where ANS senses a homogeneous solvation shell. ANS complexation by cyclodextrins or bovine serum albumin (BSA) results in a nonhomogeneous solvation shell that is reflected by nonsynchronous variation of fluorescence properties. Steady-state fluorescence and saturation transfer difference NMR experiments allow us to conclude the formation of 1:1 and 2:1 host/guest complexes through the aniline or naphthalene moieties of ANS with cyclodextrins. This nonhomogeneous solvation shell has been ignored in studies using ANS to sense the microenvironment of proteins, micelles, bilayers, and other organized systems. ANS interaction with BSA reflects the existence of a large number of binding pockets in the surface of the protein that can be classified into two well-differentiated categories.
authors.affiliation: Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Departamento de Química Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Pereira-Vilar
authors.affiliation: Unidad de Resonancia Magnética (RIAIDT), Edif. CACTUS, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Martin-Pastor
authors.affiliation: Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa , 2829-516 Monte de Caparica, Portugal.
authors.forename: Marcia
authors.initials: M
authors.lastname: Pessêgo
authors.affiliation: Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Departamento de Química Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: García-Río