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2qrw
From Proteopedia
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|PDB= 2qrw |SIZE=350|CAPTION= <scene name='initialview01'>2qrw</scene>, resolution 1.93Å | |PDB= 2qrw |SIZE=350|CAPTION= <scene name='initialview01'>2qrw</scene>, resolution 1.93Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=CYN:CYANIDE+ION'>CYN</scene>, <scene name='pdbligand= | + | |LIGAND= <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> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= glbO ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1773 Mycobacterium tuberculosis]) | |GENE= glbO ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1773 Mycobacterium tuberculosis]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1ngk|1NGK]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2qrw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qrw OCA], [http://www.ebi.ac.uk/pdbsum/2qrw PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2qrw RCSB]</span> | ||
}} | }} | ||
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[[Category: Bolognesi, M.]] | [[Category: Bolognesi, M.]] | ||
[[Category: Milani, M.]] | [[Category: Milani, M.]] | ||
| - | [[Category: CYN]] | ||
| - | [[Category: HEM]] | ||
| - | [[Category: SO4]] | ||
[[Category: alpha helix]] | [[Category: alpha helix]] | ||
[[Category: heme]] | [[Category: heme]] | ||
| Line 38: | Line 38: | ||
[[Category: truncated hemoglobin fold]] | [[Category: truncated hemoglobin fold]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:52:39 2008'' |
Revision as of 01:52, 31 March 2008
| |||||||
| , resolution 1.93Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , | ||||||
| Gene: | glbO (Mycobacterium tuberculosis) | ||||||
| Related: | 1NGK
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal stucture of Mycobacterium tuberculosis trHbO WG8F mutant
Overview
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.
About this Structure
2QRW is a Single protein structure of sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Mon Mar 31 04:52:39 2008
