1yhu
From Proteopedia
(New page: 200px<br /> <applet load="1yhu" size="450" color="white" frame="true" align="right" spinBox="true" caption="1yhu, resolution 3.15Å" /> '''Crystal structure o...) |
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| - | [[Image:1yhu.gif|left|200px]]<br /> | + | [[Image:1yhu.gif|left|200px]]<br /><applet load="1yhu" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1yhu" size=" | + | |
caption="1yhu, resolution 3.15Å" /> | caption="1yhu, resolution 3.15Å" /> | ||
'''Crystal structure of Riftia pachyptila C1 hemoglobin reveals novel assembly of 24 subunits.'''<br /> | '''Crystal structure of Riftia pachyptila C1 hemoglobin reveals novel assembly of 24 subunits.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Key to the remarkable ability of vestimentiferan tubeworms to thrive in | + | Key to the remarkable ability of vestimentiferan tubeworms to thrive in the harsh conditions of hydrothermal vents are hemoglobins that permit the sequestration and delivery of hydrogen sulfide and oxygen to chemoautotrophic bacteria. Here, we demonstrate that zinc ions, not free cysteine residues, bind sulfide in vestimentiferan hemoglobins. The crystal structure of the C1 hemoglobin from the hydrothermal vent tubeworm Riftia pachyptila has been determined to 3.15 A and revealed the unexpected presence of 12 tightly bound Zn(2+) ions near the threefold axes of this D(3) symmetric hollow sphere. Chelation experiments on R. pachyptila whole-coelomic fluid and purified hemoglobins reveal a role for Zn(2+) ions in sulfide binding. Free cysteine residues, previously proposed as sulfide-binding sites in vestimentiferan hemoglobins, are found buried in surprisingly hydrophobic pockets below the surface of the R. pachyptila C1 molecule, suggesting that access of these residues to environmental sulfide is restricted. Attempts to reduce the sulfide-binding capacities of R. pachyptila hemoglobins by addition of a thiol inhibitor were also unsuccessful. These findings challenge the currently accepted paradigm of annelid hemoglobin evolution and adaptation to reducing environments. |
==About this Structure== | ==About this Structure== | ||
| - | 1YHU is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Riftia_pachyptila Riftia pachyptila] with ZN, HEM and OXY as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1YHU is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Riftia_pachyptila Riftia pachyptila] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=OXY:'>OXY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1YHU OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Riftia pachyptila]] | [[Category: Riftia pachyptila]] | ||
| - | [[Category: Carney, S | + | [[Category: Carney, S L.]] |
| - | [[Category: Fisher, C | + | [[Category: Fisher, C R.]] |
| - | [[Category: Flores, J | + | [[Category: Flores, J F.]] |
| - | [[Category: Freytag, J | + | [[Category: Freytag, J K.]] |
| - | [[Category: Green, B | + | [[Category: Green, B N.]] |
| - | [[Category: Royer, W | + | [[Category: Royer, W E.]] |
| - | [[Category: Schaeffer, S | + | [[Category: Schaeffer, S W.]] |
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: OXY]] | [[Category: OXY]] | ||
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[[Category: hemoglobin]] | [[Category: hemoglobin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:05:27 2008'' |
Revision as of 14:05, 21 February 2008
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Crystal structure of Riftia pachyptila C1 hemoglobin reveals novel assembly of 24 subunits.
Overview
Key to the remarkable ability of vestimentiferan tubeworms to thrive in the harsh conditions of hydrothermal vents are hemoglobins that permit the sequestration and delivery of hydrogen sulfide and oxygen to chemoautotrophic bacteria. Here, we demonstrate that zinc ions, not free cysteine residues, bind sulfide in vestimentiferan hemoglobins. The crystal structure of the C1 hemoglobin from the hydrothermal vent tubeworm Riftia pachyptila has been determined to 3.15 A and revealed the unexpected presence of 12 tightly bound Zn(2+) ions near the threefold axes of this D(3) symmetric hollow sphere. Chelation experiments on R. pachyptila whole-coelomic fluid and purified hemoglobins reveal a role for Zn(2+) ions in sulfide binding. Free cysteine residues, previously proposed as sulfide-binding sites in vestimentiferan hemoglobins, are found buried in surprisingly hydrophobic pockets below the surface of the R. pachyptila C1 molecule, suggesting that access of these residues to environmental sulfide is restricted. Attempts to reduce the sulfide-binding capacities of R. pachyptila hemoglobins by addition of a thiol inhibitor were also unsuccessful. These findings challenge the currently accepted paradigm of annelid hemoglobin evolution and adaptation to reducing environments.
About this Structure
1YHU is a Protein complex structure of sequences from Riftia pachyptila with , and as ligands. Full crystallographic information is available from OCA.
Reference
Sulfide binding is mediated by zinc ions discovered in the crystal structure of a hydrothermal vent tubeworm hemoglobin., Flores JF, Fisher CR, Carney SL, Green BN, Freytag JK, Schaeffer SW, Royer WE Jr, Proc Natl Acad Sci U S A. 2005 Feb 22;102(8):2713-8. Epub 2005 Feb 14. PMID:15710902
Page seeded by OCA on Thu Feb 21 16:05:27 2008
Categories: Protein complex | Riftia pachyptila | Carney, S L. | Fisher, C R. | Flores, J F. | Freytag, J K. | Green, B N. | Royer, W E. | Schaeffer, S W. | HEM | OXY | ZN | Globin fold | Hemoglobin
