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Hydroxylamine-induced oxidation of ferrous carbonylated truncated hemoglobins from Mycobacterium tuberculosis and Campylobacter jejuni is limited by carbon monoxide dissociation.
Ascenzi, Paolo; Ciaccio, Chiara; Gasperi, Tecla; Pesce, Alessandra; Caporaso, Lucia; Coletta, Massimo.
Afiliación
  • Ascenzi P; Interdepartmental Laboratory for Electron Microscopy, Roma Tre University, 00146, Rome, Italy. ascenzi@uniroma3.it.
  • Ciaccio C; Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", 00133, Rome, Italy.
  • Gasperi T; Interuniversity Consortium for the Research on Chemistry of Metals in Biological Systems, 70126, Bari, Italy.
  • Pesce A; Department of Sciences, Roma Tre University, 00146, Rome, Italy.
  • Caporaso L; Department of Physics, University of Genova, 16146, Genoa, Italy.
  • Coletta M; Department of Mathematics and Physics, Roma Tre University, 00146, Rome, Italy.
J Biol Inorg Chem ; 22(6): 977-986, 2017 Aug.
Article en En | MEDLINE | ID: mdl-28646425
Hydroxylamine (HA) is an oxidant of ferrous globins and its action has been reported to be inhibited by CO, even though this mechanism has not been clarified. Here, kinetics of the HA-mediated oxidation of ferrous carbonylated Mycobacterium tuberculosis truncated hemoglobin N and O (Mt-trHbN(II)-CO and Mt-trHbO(II)-CO, respectively) and Campylobacter jejuni truncated hemoglobin P (Cj-trHbP(II)-CO), at pH 7.2 and 20.0 °C, are reported. Mixing Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO solution with the HA solution brings about absorption spectral changes reflecting the disappearance of the ferrous carbonylated derivatives with the concomitant formation of the ferric species. HA oxidizes irreversibly Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO with the 1:2 stoichiometry. The dissociation of CO turns out to be the rate-limiting step for the oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO by HA. Values of the second-order rate constant for HA-mediated oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO range between 8.8 × 104 and 8.6 × 107 M-1 s-1, reflecting different structural features of the heme distal pocket. This study (1) demonstrates that the inhibitory effect of CO is linked to the dissociation of this ligand, giving a functional basis to previous studies, (2) represents the first comparative investigation of the oxidation of ferrous carbonylated bacterial 2/2 globins belonging to the N, O, and P groups by HA, (3) casts light on the correlation between kinetics of HA-mediated oxidation and carbonylation of globins, and (4) focuses on structural determinants modulating the HA-induced oxidation process.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Monóxido de Carbono / Campylobacter jejuni / Hidroxilamina / Hemoglobinas Truncadas / Hierro / Mycobacterium tuberculosis Idioma: En Revista: J Biol Inorg Chem Asunto de la revista: BIOQUIMICA Año: 2017 Tipo del documento: Article País de afiliación: Italia Pais de publicación: Alemania
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Monóxido de Carbono / Campylobacter jejuni / Hidroxilamina / Hemoglobinas Truncadas / Hierro / Mycobacterium tuberculosis Idioma: En Revista: J Biol Inorg Chem Asunto de la revista: BIOQUIMICA Año: 2017 Tipo del documento: Article País de afiliación: Italia Pais de publicación: Alemania