Artículo
Ligand Binding to Chlorite Dismutase from Magnetospirillum sp.
De Schutter, Amy; Correia, Hugo D.; Freire, Diana M.; Rivas, Maria Gabriela
; Rizzi, Alberto Claudio; Santos Silva, Teresa; González, Pablo Javier
; Van Doorslaer, Sabine
Fecha de publicación:
10/2015
Editorial:
American Chemical Society
Revista:
Journal of Physical Chemistry B
ISSN:
1520-6106
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Chlorite dismutase (Cld) catalyzes the reduction of chlorite to chloride and dioxygen. Here, the ligand binding to Cld of Magnetospirillum sp. (MaCld) is investigated with X-ray crystallography and electron paramagnetic resonance (EPR). EPR reveals a large heterogeneity in the structure of wild-type MaCld, showing a variety of low- and high-spin ferric heme forms. Addition of an axial ligand, such as azide or imidazole, removes this heterogeneity almost entirely. This is in line with the two high resolution crystal structures of MaCld obtained in the presence of azide and thiocyanate that show the coordination of the ligands to the heme iron. The crystal structure of the MaCld–azide complex reveals a single well-defined orientation of the azide molecule in the heme pocket. EPR shows, however, a pH-dependent heme structure, probably due to acid–base transitions of the surrounding amino-acid residues stabilizing azide. For the azide and imidazole complex of MaCld, the hyperfine and nuclear quadrupole interactions with the close-by 14N and 1H nuclei are determined using pulsed EPR. These values are compared to the corresponding data for the low-spin forms observed in the ferric wild-type MaCld and to existing EPR data on azide and imidazole complexes of other heme proteins.
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Articulos(CCT - SANTA FE)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - SANTA FE
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - SANTA FE
Citación
De Schutter, Amy; Correia, Hugo D.; Freire, Diana M.; Rivas, Maria Gabriela; Rizzi, Alberto Claudio; et al.; Ligand Binding to Chlorite Dismutase from Magnetospirillum sp.; American Chemical Society; Journal of Physical Chemistry B; 119; 43; 10-2015; 13859-13869
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