2qrw: Difference between revisions

<table><tr><td colspan='2'>[[2qrw]] is a 12 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=2QRW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2QRW 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]] 1.93&#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=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=2qrw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qrw OCA], [https://pdbe.org/2qrw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2qrw RCSB], [https://www.ebi.ac.uk/pdbsum/2qrw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2qrw ProSAT]</span></td></tr>

[https://www.uniprot.org/uniprot/TRHBO_MYCTU TRHBO_MYCTU] When expressed in E.coli and M.smegmatis, HbO increases oxygen uptake. Membrane vesicles of E.coli carrying HbO show a respiration activity about twice that of membranes without HbO. HbO seems to interact with a terminal oxidase. Therefore, HbO could participate in oxygen/electron-transfer process, suggesting a function related to the facilitation of oxygen transfer during aerobic metabolism of M.tuberculosis.

    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/qr/2qrw_consurf.spt"</scriptWhenChecked>

    <text>to colour the structure by Evolutionary Conservation</text>

</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=2qrw ConSurf].

The crystal structure of the cyano-met form of Mt-trHbO revealed two unusual distal residues Y(CD1) and W(G8) forming a hydrogen-bond network with the heme-bound ligand [Milani, M., et al. (2003) Proc. Natl. Acad. Sci. U.S.A. 100, 5766-5771]. W(G8) is an invariant residue in group II and group III trHbs and has no counterpart in other globins. A previous study reported that changing Y(CD1) for a Phe causes a significant increase in the O2 combination rate, but almost no change in the O2 dissociation rate [Ouellet, H., et al. (2003) Biochemistry 42, 5764-5774]. Here we investigated the role of the W(G8) in ligand binding by using resonance Raman spectroscopy, stopped-flow spectrophotometry, and X-ray crystallography. For this purpose, W(G8) was changed, by site-directed mutagenesis, to a Phe in both the wild-type protein and the mutant Y(CD1)F to create the single mutant W(G8)F and the double mutant Y(CD1)F/W(G8)F, respectively. Resonance Raman results suggest that W(G8) interacts with the heme-bound O2 and CO, as evidenced by the increase of the Fe-O2 stretching mode from 559 to 564 cm-1 and by the lower frequency of the Fe-CO stretching modes (514 and 497 cm-1) compared to that of the wild-type protein. Mutation of W(G8) to Phe indicates that this residue controls ligand binding, as evidenced by a dramatic increase of the combination rates of both O2 and CO. Also, the rate of O2 dissociation showed a 90-1000-fold increase in the W(G8)F and Y(CD1)F/W(G8)F mutants, that is in sharp contrast with the values obtained for the other distal mutants Y(B10)F and Y(CD1)F [Ouellet, H., et al. (2003) Biochemistry 42, 5764-5774]. Taken together, these data indicate a pivotal role for the W(G8) residue in O2 binding and stabilization.

The roles of Tyr(CD1) and Trp(G8) in Mycobacterium tuberculosis truncated hemoglobin O in ligand binding and on the heme distal site architecture.,Ouellet H, Milani M, LaBarre M, Bolognesi M, Couture M, Guertin M Biochemistry. 2007 Oct 16;46(41):11440-50. Epub 2007 Sep 22. PMID:17887774<ref>PMID:17887774</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

<div class="pdbe-citations 2qrw" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Large Structures]]

[[Category: Bolognesi M]]

[[Category: Milani M]]