View source for 2gkm


==Crystal structure of Mycobacterium tuberculosis trHbN TyrB10Phe mutant==
<StructureSection load='2gkm' size='340' side='right'caption='[[2gkm]], [[Resolution|resolution]] 1.73&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2gkm]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycobacterium_tuberculosis Mycobacterium tuberculosis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GKM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2GKM 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]] 1.731&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CYN:CYANIDE+ION'>CYN</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</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=2gkm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2gkm OCA], [https://pdbe.org/2gkm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2gkm RCSB], [https://www.ebi.ac.uk/pdbsum/2gkm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2gkm ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TRHBN_MYCTU TRHBN_MYCTU] Binds oxygen cooperatively with very high affinity (P(50) = 0.013 mmHg at 20 degrees Celsius) because of a fast combination (25 microM(-1).s(-1)) and a slow dissociation (0.2 s(-1)) rate.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gk/2gkm_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2gkm ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
The crystallographic structure of oxygenated trHbN from Mycobacterium tuberculosis showed an extended heme distal site hydrogen-bonding network that includes Y(B10), Q(E11), and the bound O(2) (Milani, M., et al. (2001) EMBO J. 20, 3902-3909). In the present work, we analyze the effects that substitutions at the B10 and E11 positions exert on the heme and its coordinated ligands, using steady-state resonance Raman spectroscopy, absorption spectroscopy and X-ray crystallography. Our results show that (1) residues Y(B10) and Q(E11) control the binding and the ionization state of the heme-bound water molecules in ferric trHbN and are important in keeping the sixth coordination position vacant in deoxy trHbN; (2) residue Q(E11) plays a role in maintaining the integrity of the proximal Fe-His bond in deoxy trHbN; (3) in wild-type oxy-trHbN, the size and hydrogen-bonding capability of residue E11 is important to sustain proper interaction between Y(B10) and the heme-bound O(2); (4) CO-trHbN is in a conformational equilibrium, where either the Y(B10) or the Q(E11) residue interacts with the heme-bound CO; and (5) Y(B10) and Q(E11) residues control the conformation (and likely the dynamics) of the protein matrix tunnel gating residue F(E15). These findings suggest that the functional processes of ligand binding and diffusion are controlled in trHbN through the dynamic interaction of residues Y(B10), Q(E11), F(E15), and the heme ligand.

Ligand interactions in the distal heme pocket of Mycobacterium tuberculosis truncated hemoglobin N: roles of TyrB10 and GlnE11 residues.,Ouellet Y, Milani M, Couture M, Bolognesi M, Guertin M Biochemistry. 2006 Jul 25;45(29):8770-81. PMID:16846220<ref>PMID:16846220</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 2gkm" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mycobacterium tuberculosis]]
[[Category: Bolognesi M]]
[[Category: Milani M]]