Ignacio Boron

Publications (3)10.86 Total impact

• Article: Biophysical characterisation of neuroglobin of the icefish, a natural knockout for hemoglobin and myoglobin. Comparison with human neuroglobin.

  Daniela Giordano, Ignacio Boron, Stefania Abbruzzetti, Wendy Van Leuven, Francesco P Nicoletti, Flavio Forti, Stefano Bruno, C-H Christina Cheng, Luc Moens, Guido di Prisco, Alejandro D Nadra, Darío Estrin, Giulietta Smulevich, Sylvia Dewilde, Cristiano Viappiani, Cinzia Verde
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  ABSTRACT: The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe(2+) form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins.Comparison of structural and functional properties suggests that the two Antarctic fish neuroglobins most likely preserved and possibly improved the function recently proposed for human neuroglobin in ligand multichemistry. Despite subtle differences, the adaptation of Antarctic fish neuroglobins does not seem to parallel the dramatic adaptation of the oxygen carrying globins, hemoglobin and myoglobin, in the same organisms.
  PLoS ONE 01/2012; 7(12):e44508. · 4.09 Impact Factor
• Article: A protective protein matrix improves the discrimination of nitroxyl from nitric oxide by MnIII protoporphyrinate IX in aerobic media.

  Ignacio Boron, Sebastián A Suárez, Fabio Doctorovich, Marcelo A Martí, Sara E Bari
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  ABSTRACT: The selectivity of MnIII/II porphyrinates toward nitroxyl or nitric oxide donors provides a convenient starting point for the development of new materials for the speciation of these nitrogen-containing redox relatives. In the present report, we describe the insertion of MnIII protoporphyrinate IX in apomyoglobin and its chemical behavior toward HNO or NO donors, either under anaerobic or aerobic conditions. For comparison and discussion, the MnIII porphyrinate, devoid of the protein matrix, was studied in parallel. The MnIII reconstituted globin successfully reacted with the nitroxyl donor trioxodinitrate, while it was unreactive toward NO or NO donors, in good agreement with previously reported data on water soluble MnIII porphyrinates. The estimated association rate constant for the reaction with the nitroxyl donor was of the same order of magnitude for the reconstituted globin and the free porphyrinate, suggesting that the protein environment is not involved in the reaction mechanism. In contrast, the reaction product exhibited enhanced stability in the presence of dioxygen only when the porphyrinate was included in the protein matrix; this feature is ascribed to the role of the distal residues on the metal centered reactivity. This behavior is required for spectroscopic detection under biologically relevant conditions.
  Journal of inorganic biochemistry 08/2011; 105(8):1044-9. · 3.25 Impact Factor
• Article: Structure and dynamics of Antarctic fish neuroglobin assessed by computer simulations.

  Ignacio Boron, Roberta Russo, Leonardo Boechi, C-H Christina Cheng, Guido di Prisco, Darío A Estrin, Cinzia Verde, Alejandro D Nadra
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  ABSTRACT: Neuroglobin (Ngb) is a heme protein, highly conserved along evolution, predominantly found in the nervous system. It is upregulated by hypoxia and ischemia and may have a neuroprotective role under hypoxic stress. Although many other roles have been proposed, the physiological function is still unclear. Antarctic icefishes lack hemoglobin and some species also lack myoglobin, but all have Ngb and thus may help the elucidation of Ngb function. We present the first theoretically derived structure of fish Ngb and describe its behavior using molecular dynamics simulations. Specifically, we sequenced and analyzed Ngbs from a colorless-blooded Antarctic icefish species Chaenocephalus aceratus and a related red-blooded species (Dissostichus mawsoni). Both fish Ngbs are 6-coordinated but have some peculiarities that differentiate them from mammalian counterparts: they have extensions in the N and C termini that can interact with the EF loop, and a gap in the alignment that changes the CD-region structure/dynamics that has been found to play a key role in human neuroglobin. Our results suggest that a single mutation between both fish Ngbs is responsible for significant difference in the behavior of the proteins. The functional role of these characteristics is discussed.
  International Union of Biochemistry and Molecular Biology Life 03/2011; 63(3):206-13. · 3.51 Impact Factor