English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/10247
Compartir / Impacto:
Estadísticas
Add this article to your Mendeley library MendeleyBASE
Citado 42 veces en Web of Knowledge®  |  Pub MebCentral Ver citas en PubMed Central  |  Ver citas en Google académico
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Título

Protein radicals in fungal versatile peroxidase: Catalytic tryptophan radical in both Compound-I and Compound-II and studies on W164Y, W164H and W164S variants

Otros títulosProtein Radicals in Versatile Peroxidase [Running title]
AutorRuiz-Dueñas, F. J. ; Pogni, Rebecca; Morales, María ; Giansanti, Stefania; Maté, María J. ; Romero, Antonio ; Martínez, María Jesús ; Basosi, Riccardo; Martínez, Ángel T.
Fecha de publicación21-ene-2009
EditorAmerican Society for Biochemistry and Molecular Biology
CitaciónJournal of Biological Chemistry, doi: 10.1074/jbc.M808069200
ResumenLignin-degrading peroxidases, a group of biotechnologically-interesting enzymes,?oxidize high redox-potential aromatics via an exposed protein radical. Low-temperature EPR of Pleurotus eryngii versatile peroxidase (VP) revealed, for the first time in a fungal peroxidase, the presence of a tryptophanyl radical in both the two-electron (VPI) and one-electron (VPII) activated forms of the enzyme. Site-directed mutagenesis was used to substitute this tryptophan (Trp164) by tyrosine and histidine residues. No changes in the crystal structure were observed indicating that the modified behavior was due exclusively to the mutations introduced. EPR revealed the formation of tyrosyl radicals in both VPI and VPII of the W164Y variant. However, no protein radical was detected in the W164H variant, whose VPI spectrum indicated a porphyrin radical identical to that of the inactive W164S. Stopped-flow spectrophotometry showed that the W164Y mutation reduced 10-fold the apparent second-order rate constant for VPI reduction (k2app) by veratryl alcohol (VA), compared with over 50-fold reduction in W164S, revealing some catalytic activity of the tyrosine radical. Its first-order rate constant (k2) was more affected than the dissociation constant (KD2). Moreover, VPII reduction by VA was impaired by the above mutations revealing that the Trp164 radical was involved in catalysis by both VPI and VPII. The low first-order rate constant (k3) values were similar for the W164Y, W164H and W164S variants, indicating that the tyrosyl radical in VPII was not able to oxidize VA (in contrast with that observed for VPI). VPII self-reduction was also suppressed revealing that Trp164 is involved in this autocatalytic process.
DescripciónPMID: 19158088 [PubMed].-- Free full-text at the publisher's site.-- Article in press.
Versión del editorhttp://dx.doi.org/10.1074/jbc.M808069200
URI10261/10247
DOI10.1074/jbc.M808069200
ISSN0021-9258
Aparece en las colecciones: (CIB) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
accesoRestringido.pdf15,38 kBAdobe PDFVista previa
Visualizar/Abrir
Mostrar el registro completo
 



NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.