2h8d

Crystal structure of deoxy hemoglobin from Trematomus bernacchii at pH 8.4

spinqualitylabelsall models 2h8d, resolution 1.78Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2h8d is a 4 chain structure with sequence from Trematomus bernacchii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.78Å Ligands: ACE, HEM, K Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function HBA_TREBE Involved in oxygen transport from gills to the various peripheral tissues. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The Root effect is a widespread property in fish hemoglobins (Hbs) that produces a drastic reduction of cooperativity and oxygen-binding ability at acidic pH. Here, we report the high-resolution structure of the deoxy form of Hb isolated from the Antarctic fish Trematomus bernacchii (HbTb) crystallized at pH 6.2 and 8.4. The structure at acidic pH has been previously determined at a moderate resolution (Ito et al., J Mol Biol 1995;250:648-658). Our results provide a clear picture of the events occurring upon the pH increase from 6.2 to 8.4, observed within a practically unchanged crystal environment. In particular, at pH 8.4, the interaspartic hydrogen bond at the alpha(1)beta(2) interface is partially broken, suggesting a pK(a) close to 8.4 for Asp95alpha. In addition, a detailed survey of the histidine modifications, caused by the change in pH, also indicates that at least three hot regions of the molecule are modified (Ebeta helix, Cbeta-tail, CDalpha corner) and can be considered to be involved at various levels in the release of the Root protons. Most importantly, at the CDalpha corner, the break of the salt bridge Asp48alpha-His55alpha allows us to describe a detailed mechanism that transmits the modification from the CDalpha corner far to the alpha heme. More generally, the results shed light on the role played by the histidine residues in modulating the strength of the Root effect and also support the emerging idea that the structural determinants, at least for a part of the Root effect, are specific of each Hb endowed with this property. High resolution crystal structure of deoxy hemoglobin from Trematomus bernacchii at different pH values: the role of histidine residues in modulating the strength of the root effect.,Mazzarella L, Vergara A, Vitagliano L, Merlino A, Bonomi G, Scala S, Verde C, di Prisco G Proteins. 2006 Nov 1;65(2):490-8. PMID:16909420 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hemoglobin 3D structures

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