View source for 3qqq


==Crystal structure of non-symbiotic plant hemoglobin from Trema tomentosa==
<StructureSection load='3qqq' size='340' side='right'caption='[[3qqq]], [[Resolution|resolution]] 1.84&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3qqq]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Trema_tomentosum Trema tomentosum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QQQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3QQQ 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]] 1.84&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=3qqq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qqq OCA], [https://pdbe.org/3qqq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3qqq RCSB], [https://www.ebi.ac.uk/pdbsum/3qqq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3qqq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HBL_TRETO HBL_TRETO] May not function as an oxygen storage or transport protein, but might act as an oxygen sensor or play a role in electron transfer, possibly to a bound oxygen molecule.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Hemoglobins from the plants Parasponia andersonii (ParaHb) and Trema tomentosa (TremaHb) are 93% identical in primary structure but differ in oxygen binding constants in accordance with their distinct physiological functions. Additionally, these proteins are dimeric, and ParaHb exhibits the unusual property of having different heme redox potentials for each subunit. To investigate how these hemoglobins could differ in function despite their shared sequence identity, and to determine the cause of subunit heterogeneity in ParaHb, we have measured their crystal structures in the ferric oxidation state. Furthermore, we have made a monomeric ParaHb mutant protein (I43N) and measured its ferrous/ferric heme redox potential to test the hypothesized link between quaternary structure and heme heterogeneity in wild type ParaHb. Our results demonstrate that TremaHb is a symmetric dimeric hemoglobin similar to other class 1 nonsymbiotic plant hemoglobins, but that ParaHb has structurally distinct heme coordination in each of its two subunits that is absent in the monomeric I43N mutant protein. A mechanism for achieving structural heterogeneity in ParaHb is proposed, in which the Ile101(F4) side chain contacts the proximal His105(F8) in one subunit but not the other. These results are discussed in the context of the evolution of plant oxygen transport hemoglobins, and other potential functions of plant hemoglobins.

Crystal Structures of Parasponia and Trema Hemoglobins; Differential Heme Coordination is Linked to Quaternary Structure.,Kakar S, Sturms R, Tiffany A, Nix JC, Dispirito AA, Hargrove MS Biochemistry. 2011 Apr 14. PMID:21491905<ref>PMID:21491905</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3qqq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Hemoglobin 3D structures|Hemoglobin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Trema tomentosum]]
[[Category: Dispirito A]]
[[Category: Hargrove MS]]
[[Category: Kakar S]]
[[Category: Nix JC]]
[[Category: Savage A]]
[[Category: Sturms R]]