title: The binding of zinc(II) to Mung Bean Nuclease. A voltammetric study.
abstract: Binding of zinc to Mung Bean Nuclease was investigated by anodic stripping voltammetry and cyclic voltammetry. These methods rely on the direct monitoring of the oxidation current of zinc in the absence and presence of Mung Bean Nuclease. Titration curves of Zn(2+) with the enzyme were obtained in concentrations ranging from 1.08x10(-9) to 1.07x10(-8) M and 1.16x10(-8) to 1.04x10(-7) M. The acquired data were used to calculate the dissociation constant and the stoichiometry of the complex. The binding sites of zinc in the Mung Bean Nuclease molecule were investigated using cyclic voltammetry. Two types of binding sites for zinc were identified and were attributed to a mononuclear exposed zinc-binding site with catalytic function and to an inaccessible binuclear zinc-binding site with structural functions.
authors.affiliation: Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, Final W5 norte, PO Box 02372, 70.770-900, Brasília-DF, Brazil. clarissa@cenargen.embrapa.br
authors.forename: Clarissa Silva
authors.initials: CS
authors.lastname: Pires de Castro
authors.forename: Jurandir
authors.initials: J
authors.lastname: Rodrigues SouzaDe
authors.forename: Carlos
authors.initials: C
authors.lastname: Bloch Júnior
mesh_terms: D001665:Binding Sites; D002413:Cations, Divalent; D004563:Electrochemistry / Q000379:methods; D007700:Kinetics; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism*; D017186:Titrimetry / Q000379:methods; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D015719:Single-Strand Specific DNA and RNA Endonucleases; D015032:Zinc