title: Structure-activity relationships on the study of β-galactosidase folding/unfolding due to interactions with immobilization additives: Triton X-100 and ethanol.
abstract: Improving the enzyme stability is a challenge for allowing their practical application. The surfactants are stabilizing agents, however, there are still questions about their influence on enzyme properties. The structure-activity/stability relationship for β-galactosidase from Bacillus circulans is studied here by Circular Dichroism and activity measurements, as a function of temperature and pH. The tendency of preserving the β-sheet and α-helix structures at temperatures below 65°C and different pH is the result of the balance between the large- and short-range effects, respecting to the active site. This information is fundamental for explaining the structural changes of this enzyme in the presence of Triton X-100 surfactant and ethanol. The enzyme thermal stabilization in the presence of this surfactant responds to the rearrangement of the secondary structure for having optimal activity/stability. The effect of ethanol is more related with changes in the dielectric properties of the aqueous solution than with protein structural transformations. These results contribute to understand the effects of surfactant-enzyme interactions on the enzyme behavior, from the structural point of view and to rationalize the surfactant-based stabilizing strategies for β-galactosidades.
authors.affiliation: Grupo Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia - UdeA, Calle 70 No. 52-21, Medellín, Colombia.
authors.forename: Dayana
authors.initials: D
authors.lastname: Soto
authors.affiliation: Grupo Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia - UdeA, Calle 70 No. 52-21, Medellín, Colombia.
authors.forename: Sindy
authors.initials: S
authors.lastname: Escobar
authors.affiliation: Laboratorio de Síntesis de Péptidos e Inmunología Molecular, Pontificia Universidad Católica de Valparaíso, Núcleo de Biotecnología Curauma, Valparaíso, Chile.
authors.forename: Fanny
authors.initials: F
authors.lastname: Guzmán
authors.affiliation: Laboratorio de Síntesis de Péptidos e Inmunología Molecular, Pontificia Universidad Católica de Valparaíso, Núcleo de Biotecnología Curauma, Valparaíso, Chile.
authors.forename: Constanza
authors.initials: C
authors.lastname: Cárdenas
authors.affiliation: Departamento de Ingeniería de Alimentos, Universidad de La Serena, Raul Bitran 1305, La Serena, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bernal
authors.affiliation: Grupo Ciencia de los Materiales, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia - UdeA, Calle 70 No. 52-21, Medellín, Colombia. Electronic address: monica.mesa@udea.edu.com.
authors.forename: Monica
authors.initials: M
authors.lastname: Mesa
mesh_terms: D001407:Bacillus / Q000201:enzymology; D004795:Enzyme Stability / Q000187:drug effects; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism*; D000431:Ethanol / Q000737:chemistry / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008958:Models, Molecular; D017830:Octoxynol / Q000737:chemistry / Q000494:pharmacology*; D000072756:Protein Conformation, alpha-Helical / Q000187:drug effects; D000072757:Protein Conformation, beta-Strand / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects*; D013329:Structure-Activity Relationship; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology; D013696:Temperature; D001616:beta-Galactosidase / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D013501:Surface-Active Agents; D000431:Ethanol; D017830:Octoxynol; D001616:beta-Galactosidase
keywords: Circular dichroism; Structure/activity relationships; β-galactosidase