Artículo
Reactivity of inorganic sulfide species toward a heme protein model
Bieza, Silvina Andrea
; Boubeta, Fernando Martín
; Feis, Alessandro; Smulevich, Giulietta; Estrin, Dario Ariel
; Boechi, Leonardo
; Bari, Sara Elizabeth
Fecha de publicación:
01/2015
Editorial:
American Chemical Society
Revista:
Inorganic Chemistry
ISSN:
0020-1669
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The reactivity of inorganic sulfide species toward heme peptides was explored under biorelevant conditions in order to unravel the molecular details of the reactivity of the endogenous hydrogen sulfide toward heme proteins. Unlike ferric porphyrinates, which are reduced by inorganic sulfide, some heme proteins can form stable FeIII-sulfide adducts. To isolate the protein factors ruling the redox chemistry, we used as a system model, the undecapeptide microperoxidase (MP11), a heme peptide derived from cytochrome c proteolysis that retains the proximal histidine bound to the FeIII atom. Upon addition of gaseous hydrogen sulfide (H2S) at pH 6.8, the UV-vis spectra of MP11 closely resembled those of the low-spin ferric hydroxo complex (only attained at an alkaline pH) and cysteine or alkylthiol derivatives, suggesting that the FeIII reduction was prevented. The low-frequency region of the resonance Raman spectrum revealed the presence of an FeIII-S band at 366 cm-1 and the general features of a low-spin hexacoordinated heme. Anhydrous sodium sulfide (Na2S) was the source of sulfide of choice for the kinetic evaluation of the process. Theoretical calculations showed no distal stabilization mechanisms for bound sulfide species in MP11, highlighting a key role of the proximal histidine for the stabilization of the FeIII-S adducts of heme compounds devoid of distal counterparts, which is significant with regard to the biochemical reactivity of endogenous hydrogen sulfide.
Palabras clave:
Sulfide
,
Hemeproteins
,
Microperoxidase
Archivos asociados
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Colecciones
Articulos(INQUIMAE)
Articulos de INST.D/QUIM FIS D/L MATERIALES MEDIOAMB Y ENERGIA
Articulos de INST.D/QUIM FIS D/L MATERIALES MEDIOAMB Y ENERGIA
Articulos(OCA CIUDAD UNIVERSITARIA)
Articulos de OFICINA DE COORDINACION ADMINISTRATIVA CIUDAD UNIVERSITARIA
Articulos de OFICINA DE COORDINACION ADMINISTRATIVA CIUDAD UNIVERSITARIA
Citación
Bieza, Silvina Andrea; Boubeta, Fernando Martín; Feis, Alessandro; Smulevich, Giulietta; Estrin, Dario Ariel; et al.; Reactivity of inorganic sulfide species toward a heme protein model; American Chemical Society; Inorganic Chemistry; 54; 2; 1-2015; 527-533
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