View source for 4iro


==Crystal structure of T-state carbonmonoxy hemoglobin from Trematomus bernacchii at pH 8.4==
<StructureSection load='4iro' size='340' side='right'caption='[[4iro]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4iro]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Trematomus_bernacchii Trematomus bernacchii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4IRO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IRO FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=CMO:CARBON+MONOXIDE'>CMO</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4iro FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4iro OCA], [https://pdbe.org/4iro PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4iro RCSB], [https://www.ebi.ac.uk/pdbsum/4iro PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4iro ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Many fish hemoglobins exhibit a marked dependence of oxygen affinity and cooperativity on proton concentration, called Root effect. Both tertiary and quaternary effects have been evoked to explain the allosteric regulation brought about by protons in fish hemoglobins. However, no general rules have emerged so far. We carried out a complementary crystallographic and microspectroscopic characterization of ligand binding to crystals of deoxy-hemoglobin from the Antarctic fish Trematomus bernacchii (HbTb) at pH6.2 and pH8.4. At low pH ligation has negligible structural effects, correlating with low affinity and absence of cooperativity in oxygen binding. At high pH, ligation causes significant changes at the tertiary structural level, while preserving structural markers of the T state. These changes mainly consist in a marked displacement of the position of the switch region CD corner towards an R-like position. The functional data on T-state crystals validate the relevance of the crystallographic observations, revealing that, differently from mammalian Hbs, in HbTb a significant degree of cooperativity in oxygen binding is due to tertiary conformational changes, in the absence of the T-R quaternary transition. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.

Role of tertiary structures on the Root effect in fish hemoglobins.,Ronda L, Merlino A, Bettati S, Verde C, Balsamo A, Mazzarella L, Mozzarelli A, Vergara A Biochim Biophys Acta. 2013 Feb 1. pii: S1570-9639(13)00042-3. doi:, 10.1016/j.bbapap.2013.01.031. PMID:23376186<ref>PMID:23376186</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4iro" style="background-color:#fffaf0;"></div>

==See Also==
*[[Hemoglobin 3D structures|Hemoglobin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Trematomus bernacchii]]
[[Category: Balsamo A]]
[[Category: Mazzarella L]]
[[Category: Merlino A]]
[[Category: Vergara A]]