Spectroscopic and crystallographic characterization of bis-histidyl adducts in tetrameric hemoglobins(536 views) Vergara A, Vitagliano L, Verde C, di Prisco G, Mazzarella L
Keywords: Fish Protein, Heme, Hemoglobin, Drug Derivative, Hemoprotein, Histidine, Crystal Structure, Crystallography, Electron Spin Resonance, Molecular Model, Priority Journal, Protein Analysis, Protein Function, Protein Structure, Raman Spectrometry, Review, Spectroscopy, Structure Analysis, Three Dimensional Imaging, Animal, Antarctica, Chemical Structure, Chemistry, Crystallization, Electricity, Hemichrome, Protein Quaternary Structure, Spectrophotometry, Vertebrata, Antarctic Regions, Electrostatics, Hemeproteins,
Affiliations: *** IBB - CNR ***
Department of Chemistry and Consorzio Bioteknet, University of Naples Federico II, Naples, Italy
Institute of Biostructures and Bioimaging, CNR, Naples, Italy
Institute of Protein Biochemistry, CNR, Naples, Italy
References: Not available.
Spectroscopic and crystallographic characterization of bis-histidyl adducts in tetrameric hemoglobins
Hemoglobins (Hbs) are important proteins devoted to oxygen transport. Hbs carry out their function by keeping the iron atom, which binds the oxygen molecule, in its reduced Fe(II) state. Nonetheless, it is well known that Hbs frequently undergo, even under physiological conditions, spontaneous oxidation. Although these processes have been widely investigated, their role and impact in different biological contexts are still highly debated. In vertebrate Hbs, assembled in alpha(2)beta(2) tetramers, it has traditionally been assumed that oxidized forms endowed with nativelike structures are either aquo-met or hydroxy-met states, depending on the pH of the medium. This view has been questioned by several independent investigations. In the past, indirect evidence of the existence of alternative nativelike oxidized forms was obtained from spectroscopic analyses. Indeed, it was suggested that, in tetrameric Hbs, bis-histidyl hemichrome states could be compatible with folded structures. Recent studies performed by complementing spectroscopic and crystallo-graphic methodologies have provided a detailed picture of hemichrome structure and formation in these proteins. Here we review the methodological approaches adopted to achieve these results, the main structural features of these states, and the current hypotheses on their possible functional implications.
Spectroscopic and crystallographic characterization of bis-histidyl adducts in tetrameric hemoglobins