Impact factor: 1.87, Impact factor a 5 anni: 2.133
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Parole chiave: Aquomet, Bis-Hystidyl, Crystallography, Hemoglobin, X-Ray
, Disulfides Chemistry
, Heme Chemistry
, Hemoglobins Chemistry
, Models, Molecular
, Protein Structure, Quaternary
, Protein Subunits Chemistry,
*** IBB - CNR *** Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy Accademia di Scienze Fisiche e Matematiche della Societa Nazionale di Scienze, Lettere ed Arti in Napoli, Naples, Italy. Institute of Biostructures and Bioimaging, C.N.R., Naples, Italy. CEINGE, Napoli, Italy. Electronic address: email@example.com.
Spectroscopic studies carried out in the early seventies have shown that the beta-homotetramer of human hemoglobin (beta4-HbA) in the ferric state is a mixture of aquomet and bis-histidyl forms. Here we present the first crystal structure, solved at 2.10A resolution, of the oxidized form of beta4-HbA. The overall quaternary structure of the protein in the ferric state is virtually indistinguishable from that of the ferrous deoxygenated and carbomonoxy forms. The structure reveals that the four hemes are exclusively in an aquomet coordination, without any trace of bis-histidyl coordination. The oxidation of beta4-HbA is associated with the formation of a disulfide bridge between residues Cys112(G14) of beta1/beta4 and beta2/beta3 chains. The coordination state of beta4-HbA has been compared to that known for other organisms that exhibit bis-histidyl heme coordination in the beta4 state. This occurrence has been discussed in terms of different organism physiology.<br>
293 Records (284 escludendo Abstract e Conferenze). Impact factor totale: 1165.717 (1117.225 escludendo Abstract e Conferenze). Impact factor a 5 anni totale: 1264.736 (1191.58 escludendo Abstract e Conferenze).