Combined Crystallographic and Spectroscopic Analysis of Trematomus bernacchii Hemoglobin Highlights Analogies and Differences in the Peculiar Oxidation Pathway of Antarctic Fish Hemoglobins(262 visite) Merlino A, Vitagliano L, Howes BD, Verde C, Di Prisco G, Smulevich G, Sica F, Vergara A
Parole chiave: Autoxidation, Cold-Adaptation, Hemoglobin, Raman, X-Ray Crystallography, Air-Exposure, Binding State, Electron Densities, Ferric Species, Global Levels, Heme Pockets, High Spin State, High-Resolution Structures, Oxidation Pathway, Oxidation Process, Oxidized State, Pentacoordinated, Resonance Raman, Sequence Identity, Spectroscopic Data, Structural Correlation, Structural Similarity, Electron Spin Resonance Spectroscopy, Iron Analysis, Mineralogy, Oxidation Resistance, Porphyrins, Self Assembly, Spectroscopic Analysis, Spin Dynamics, Reaction Intermediates, X Ray Crystallography, Amino Acid, Ferrous Ion, Hemoprotein, Amino Acid Sequence, Article, Autooxidation, Fish, Nonhuman, Protein Binding, Protein Function, Protein Metabolism, Protein Modification, Protein Structure, Raman Spectrometry, Sequence Homology, Structure Analysis, Trematomus Bernacchii, Antarctica, Controlled Study, Correlation Analysis, Molecular Interaction, Protein Analysis, Animals, Antarctic Regions, Binding Sites, Fish Proteins, Hydrogen-Ion Concentration, Models, Oxidation-Reduction, Perciformes, Tertiary, Species Specificity, Spectrum Analysis, Superoxide Dismutase, Trematomus Newnesi,
*** IBB - CNR *** Department of Chemistry, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, I-80134 Naples, Italy Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy Institute of Protein Biochemistry, CNR, Via Pietro Castellino 111, I-80131 Naples, Italy
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Recent studies have demonstrated that hemoglobins isolated from Antarctic fish undergo peculiar oxidation processes. Here we show, by combining crystallographic and spectroscopic data, that the oxidation pathway of Trematomus bernacchii hemoglobin (HbTb) is distinct from that observed for the major component of Trematomus newnesi (Hb1Tn), despite the high sequence identity of the two proteins and structural similarity of their ferrous and fully oxidized states. Resonance Raman analysis of HbTb autoxidation upon air-exposure reveals the absence of the oxidized pentacoordinated state that was observed for Hb1Tn. The HbTb oxidation pathway is characterized by two ferric species and aquo hexacoordinated high spin state and a bis-histidyl hexacoordinated low spin form, which appear in the early stage of the oxidation process. The high resolution structure of an intermediate along the oxidation pathway has been determined at 1.4 angstrom resolution. The analysis of the electron density of the heme pocket shows, for both alpha and the beta iron, the coexistence of multiple binding states. In this partially oxidized form, HbTb exhibits significant deviations from the canonical R state both at the local and global level. The analysis of these modifications highlights the structural correlation between key functional regions of the protein. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 1117-1125, 2009.
86 Records (82 escludendo Abstract e Conferenze). Impact factor totale: 364.425 (329.892 escludendo Abstract e Conferenze). Impact factor a 5 anni totale: 408.913 (351.173 escludendo Abstract e Conferenze).