2g3h
From Proteopedia
(New page: 200px<br /> <applet load="2g3h" size="450" color="white" frame="true" align="right" spinBox="true" caption="2g3h, resolution 1.40Å" /> '''Cyanide Binding and...) |
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| - | [[Image:2g3h.gif|left|200px]]<br /> | + | [[Image:2g3h.gif|left|200px]]<br /><applet load="2g3h" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="2g3h" size=" | + | |
caption="2g3h, resolution 1.40Å" /> | caption="2g3h, resolution 1.40Å" /> | ||
'''Cyanide Binding and Heme Cavity Conformational Transitions in Drosophila melanogaster Hexa-coordinate Hemoglobin'''<br /> | '''Cyanide Binding and Heme Cavity Conformational Transitions in Drosophila melanogaster Hexa-coordinate Hemoglobin'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The reason for the presence of hemoglobin-like molecules in insects, such | + | The reason for the presence of hemoglobin-like molecules in insects, such as Drosophila melanogaster, that live in fully aerobic environments has yet to be determined. Heme endogenous hexacoordination (where HisE7 and HisF8 axial ligands to the heme Fe atom are both provided by the protein) is a recently discovered mechanism proposed to modulate O(2) affinity in hemoglobins from different species. Previous results have shown that D. melanogaster hemoglobin 1 (product of the glob1 gene) displays heme endogenous hexacoordination in both the ferrous and ferric states. Here we present kinetic data characterizing the exogenous cyanide ligand binding process, and the three-dimensional structure (at 1.4 A resolution) of the ensuing cyano-met D. melanogaster hemoglobin. Comparison with the crystal structure of the endogenously hexacoordinated D. melanogaster hemoglobin shows that the transition to the cyano-met form is supported by conformational readjustment in the CD-D-E region of the protein, which removes HisE7 from the heme. The structural and functional features of D. melanogaster hemoglobin are examined in light of previous results achieved for human and mouse neuroglobins and for human cytoglobin, which display heme endogenous hexacoordination. The study shows that, despite the rather constant value for cyanide association rate constants for the ferric hemoproteins, different distal site conformational readjustments and/or heme sliding mechanisms are displayed by the known hexacoordinate hemoglobins as a result of exogenous ligand binding. |
==About this Structure== | ==About this Structure== | ||
| - | 2G3H is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Drosophila_melanogaster Drosophila melanogaster] with CL, MG, CYN and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 2G3H is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Drosophila_melanogaster Drosophila melanogaster] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=CYN:'>CYN</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G3H OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Hankeln, T.]] | [[Category: Hankeln, T.]] | ||
[[Category: Moens, L.]] | [[Category: Moens, L.]] | ||
| - | [[Category: Sanctis, D | + | [[Category: Sanctis, D de.]] |
[[Category: CL]] | [[Category: CL]] | ||
[[Category: CYN]] | [[Category: CYN]] | ||
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[[Category: drosophila melanogaster hemoglobin structure; hexa-coordinate hemoglobin; cyanide binding to hemoglobin; heme distal site structure; fruit fly hemoglobin]] | [[Category: drosophila melanogaster hemoglobin structure; hexa-coordinate hemoglobin; cyanide binding to hemoglobin; heme distal site structure; fruit fly hemoglobin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:27:44 2008'' |
Revision as of 15:27, 21 February 2008
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Cyanide Binding and Heme Cavity Conformational Transitions in Drosophila melanogaster Hexa-coordinate Hemoglobin
Overview
The reason for the presence of hemoglobin-like molecules in insects, such as Drosophila melanogaster, that live in fully aerobic environments has yet to be determined. Heme endogenous hexacoordination (where HisE7 and HisF8 axial ligands to the heme Fe atom are both provided by the protein) is a recently discovered mechanism proposed to modulate O(2) affinity in hemoglobins from different species. Previous results have shown that D. melanogaster hemoglobin 1 (product of the glob1 gene) displays heme endogenous hexacoordination in both the ferrous and ferric states. Here we present kinetic data characterizing the exogenous cyanide ligand binding process, and the three-dimensional structure (at 1.4 A resolution) of the ensuing cyano-met D. melanogaster hemoglobin. Comparison with the crystal structure of the endogenously hexacoordinated D. melanogaster hemoglobin shows that the transition to the cyano-met form is supported by conformational readjustment in the CD-D-E region of the protein, which removes HisE7 from the heme. The structural and functional features of D. melanogaster hemoglobin are examined in light of previous results achieved for human and mouse neuroglobins and for human cytoglobin, which display heme endogenous hexacoordination. The study shows that, despite the rather constant value for cyanide association rate constants for the ferric hemoproteins, different distal site conformational readjustments and/or heme sliding mechanisms are displayed by the known hexacoordinate hemoglobins as a result of exogenous ligand binding.
About this Structure
2G3H is a Single protein structure of sequence from Drosophila melanogaster with , , and as ligands. Full crystallographic information is available from OCA.
Reference
Cyanide binding and heme cavity conformational transitions in Drosophila melanogaster hexacoordinate hemoglobin., de Sanctis D, Ascenzi P, Bocedi A, Dewilde S, Burmester T, Hankeln T, Moens L, Bolognesi M, Biochemistry. 2006 Aug 22;45(33):10054-61. PMID:16906763
Page seeded by OCA on Thu Feb 21 17:27:44 2008
Categories: Drosophila melanogaster | Single protein | Ascenzi, P. | Bocedi, A. | Bolognesi, M. | Burmester, T. | Dewilde, S. | Hankeln, T. | Moens, L. | Sanctis, D de. | CL | CYN | HEM | MG | Drosophila melanogaster hemoglobin structure; hexa-coordinate hemoglobin; cyanide binding to hemoglobin; heme distal site structure; fruit fly hemoglobin
