1i4z
From Proteopedia
(New page: 200px<br /><applet load="1i4z" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i4z, resolution 2.10Å" /> '''THE CRYSTAL STRUCTUR...) |
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| - | [[Image:1i4z.gif|left|200px]]<br /><applet load="1i4z" size=" | + | [[Image:1i4z.gif|left|200px]]<br /><applet load="1i4z" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i4z, resolution 2.10Å" /> | caption="1i4z, resolution 2.10Å" /> | ||
'''THE CRYSTAL STRUCTURE OF PHASCOLOPSIS GOULDII L98Y METHEMERYTHRIN'''<br /> | '''THE CRYSTAL STRUCTURE OF PHASCOLOPSIS GOULDII L98Y METHEMERYTHRIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Reported are the X-ray crystal structures of recombinant Phascolopsis | + | Reported are the X-ray crystal structures of recombinant Phascolopsis gouldii methemerythrin (1.8-A resolution) and the structure of an O2-binding-pocket mutant, L98Y methemerythrin (2.1-A resolution). The L98Y hemerythrin (Hr) has a greatly enhanced O2 affinity, a slower O2 dissociation rate, a larger solvent deuterium isotope effect on this rate, and a greater resistance to autoxidation relative to the wild-type protein. The crystal structures show that the hydrophobic binding pocket of Hr can accommodate substitution of a leucyl by a tyrosyl side chain with relatively minor structural rearrangements. UV/vis and resonance Raman spectra show that in solution L98Y methemerythrin contains a mixture of two diiron site structures differing by the absence or presence of an Fe(III)-coordinated phenolate. However, in the crystal, only one L98Y diiron site structure is seen, in which the Y98 hydroxyl is not a ligand, but instead forms a hydrogen bond to a terminal hydroxo/aqua ligand to the nearest iron. Based on this crystal structure, we propose that in the oxy form of L98Y hemerythrin the non-polar nature of the binding pocket favors localization of the Y98 hydroxyl near the O2 binding site, where it can donate a hydrogen bond to the hydroperoxo ligand. The stabilizing Y98OH-O2H-interaction would account for all of the altered O2 binding properties of L98Y Hr listed above. |
==About this Structure== | ==About this Structure== | ||
| - | 1I4Z is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phascolopsis_gouldii Phascolopsis gouldii] with FEO as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1I4Z is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phascolopsis_gouldii Phascolopsis gouldii] with <scene name='pdbligand=FEO:'>FEO</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I4Z OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Phascolopsis gouldii]] | [[Category: Phascolopsis gouldii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Farmer, C | + | [[Category: Farmer, C S.]] |
| - | [[Category: Jr., D | + | [[Category: Jr., D M.Kurtz.]] |
| - | [[Category: Liu, Z | + | [[Category: Liu, Z J.]] |
[[Category: Rose, J.]] | [[Category: Rose, J.]] | ||
| - | [[Category: Wang, B | + | [[Category: Wang, B C.]] |
[[Category: FEO]] | [[Category: FEO]] | ||
[[Category: diiron]] | [[Category: diiron]] | ||
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[[Category: oxygen binding]] | [[Category: oxygen binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:08:02 2008'' |
Revision as of 11:08, 21 February 2008
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THE CRYSTAL STRUCTURE OF PHASCOLOPSIS GOULDII L98Y METHEMERYTHRIN
Overview
Reported are the X-ray crystal structures of recombinant Phascolopsis gouldii methemerythrin (1.8-A resolution) and the structure of an O2-binding-pocket mutant, L98Y methemerythrin (2.1-A resolution). The L98Y hemerythrin (Hr) has a greatly enhanced O2 affinity, a slower O2 dissociation rate, a larger solvent deuterium isotope effect on this rate, and a greater resistance to autoxidation relative to the wild-type protein. The crystal structures show that the hydrophobic binding pocket of Hr can accommodate substitution of a leucyl by a tyrosyl side chain with relatively minor structural rearrangements. UV/vis and resonance Raman spectra show that in solution L98Y methemerythrin contains a mixture of two diiron site structures differing by the absence or presence of an Fe(III)-coordinated phenolate. However, in the crystal, only one L98Y diiron site structure is seen, in which the Y98 hydroxyl is not a ligand, but instead forms a hydrogen bond to a terminal hydroxo/aqua ligand to the nearest iron. Based on this crystal structure, we propose that in the oxy form of L98Y hemerythrin the non-polar nature of the binding pocket favors localization of the Y98 hydroxyl near the O2 binding site, where it can donate a hydrogen bond to the hydroperoxo ligand. The stabilizing Y98OH-O2H-interaction would account for all of the altered O2 binding properties of L98Y Hr listed above.
About this Structure
1I4Z is a Single protein structure of sequence from Phascolopsis gouldii with as ligand. Full crystallographic information is available from OCA.
Reference
The crystal structures of Phascolopsis gouldii wild type and L98Y methemerythrins: structural and functional alterations of the O2 binding pocket., Farmer CS, Kurtz DM Jr, Liu ZJ, Wang BC, Rose J, Ai J, Sanders-Loehr J, J Biol Inorg Chem. 2001 Apr;6(4):418-29. PMID:11372200
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