1duk: Difference between revisions
New page: left|200px<br /> <applet load="1duk" size="450" color="white" frame="true" align="right" spinBox="true" caption="1duk, resolution 2.13Å" /> '''WILD-TYPE RECOMBINA... |
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[[Image:1duk.gif|left|200px]]<br /> | [[Image:1duk.gif|left|200px]]<br /><applet load="1duk" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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caption="1duk, resolution 2.13Å" /> | caption="1duk, resolution 2.13Å" /> | ||
'''WILD-TYPE RECOMBINANT SPERM WHALE METAQUOMYOGLOBIN'''<br /> | '''WILD-TYPE RECOMBINANT SPERM WHALE METAQUOMYOGLOBIN'''<br /> | ||
==Overview== | ==Overview== | ||
The structural role of a side-chain to side-chain protein hydrogen bond is | The structural role of a side-chain to side-chain protein hydrogen bond is examined using trans-substitution of the proximal histidine of myoglobin with methylimidazoles (Barrick, Biochemistry 1994;33:6546-6554). Modification of the chemical structure of exogenous ligands allows this hydrogen bond to be disrupted. Comparison of the crystal structures of H93G myoglobin complexed 4-methylimidazole (4meimd; methylation at carbon 4) and 1-methylimidazole (1meimd; methylation at the adjacent nitrogen, preventing hydrogen bonding between the imidazole ligand and the protein) shows that the polypeptide, heme, and methylimidazole orientations are the same within error. For 4meimd there appear to be major and minor conformations corresponding to different tautomeric states of the ligand. Conformational heterogeneity is also seen in the hyperfine-shifted region of the NMR spectrum of 4meimd complexed with high-spin H93G deoxyMb. The major conformation of the 4meimd ligand and the 1meimd ligand, as seen in the respective crystal structures, are quite similar except that the proximal ligand NH-to-Ser92-OH hydrogen bond is eliminated in the 1meimd complex, and instead the proximal ligand CH is adjacent to the Ser92-OH. Thus, this system provides a means to eliminate the Mb proximal hydrogen bond in a chemically and structurally conservative way. | ||
==About this Structure== | ==About this Structure== | ||
1DUK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon] with HEM as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1DUK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon] with <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DUK OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Barrick, D.]] | [[Category: Barrick, D.]] | ||
[[Category: Dahlquist, F | [[Category: Dahlquist, F W.]] | ||
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: heme protein]] | [[Category: heme protein]] | ||
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[[Category: oxygen-storage protein]] | [[Category: oxygen-storage protein]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:20:40 2008'' | ||
Revision as of 13:20, 21 February 2008
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WILD-TYPE RECOMBINANT SPERM WHALE METAQUOMYOGLOBIN
OverviewOverview
The structural role of a side-chain to side-chain protein hydrogen bond is examined using trans-substitution of the proximal histidine of myoglobin with methylimidazoles (Barrick, Biochemistry 1994;33:6546-6554). Modification of the chemical structure of exogenous ligands allows this hydrogen bond to be disrupted. Comparison of the crystal structures of H93G myoglobin complexed 4-methylimidazole (4meimd; methylation at carbon 4) and 1-methylimidazole (1meimd; methylation at the adjacent nitrogen, preventing hydrogen bonding between the imidazole ligand and the protein) shows that the polypeptide, heme, and methylimidazole orientations are the same within error. For 4meimd there appear to be major and minor conformations corresponding to different tautomeric states of the ligand. Conformational heterogeneity is also seen in the hyperfine-shifted region of the NMR spectrum of 4meimd complexed with high-spin H93G deoxyMb. The major conformation of the 4meimd ligand and the 1meimd ligand, as seen in the respective crystal structures, are quite similar except that the proximal ligand NH-to-Ser92-OH hydrogen bond is eliminated in the 1meimd complex, and instead the proximal ligand CH is adjacent to the Ser92-OH. Thus, this system provides a means to eliminate the Mb proximal hydrogen bond in a chemically and structurally conservative way.
About this StructureAbout this Structure
1DUK is a Single protein structure of sequence from Physeter catodon with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Trans-substitution of the proximal hydrogen bond in myoglobin: I. Structural consequences of hydrogen bond deletion., Barrick D, Dahlquist FW, Proteins. 2000 Jun 1;39(4):278-90. PMID:10813811
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