1i55
From Proteopedia
(New page: 200px<br /><applet load="1i55" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i55, resolution 2.00Å" /> '''CYTOCHROME C (TUNA) ...) |
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| - | [[Image:1i55.gif|left|200px]]<br /><applet load="1i55" size=" | + | [[Image:1i55.gif|left|200px]]<br /><applet load="1i55" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i55, resolution 2.00Å" /> | caption="1i55, resolution 2.00Å" /> | ||
'''CYTOCHROME C (TUNA) WITH 2ZN:1FE MIXED-METAL PORPHYRINS'''<br /> | '''CYTOCHROME C (TUNA) WITH 2ZN:1FE MIXED-METAL PORPHYRINS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The current understanding of electron tunneling through proteins has come | + | The current understanding of electron tunneling through proteins has come from work on systems where donors and acceptors are held at fixed distances and orientations. The factors that control electron flow between proteins are less well understood, owing to uncertainties in the relative orientations and structures of the reactants during the very short time that tunneling occurs. As we report here, the way around such structural ambiguity is to examine oxidation-reduction reactions in protein crystals. Accordingly, we have measured and analyzed the kinetics of electron transfer between native and Zn-substituted tuna cytochrome c (cyt c) molecules in crystals of known structure. Electron transfer rates [(320 s(-1) for *Zn-cyt c --> Fe(III)-cyt c; 2000 s(-1) for Fe(II)-cyt c --> Zn-cyt c(+))] over a Zn-Fe distance of 24.1 A closely match those for intraprotein electron tunneling over similar donor-acceptor separations. Our results indicate that van der Waals interactions and water-mediated hydrogen bonds are effective coupling elements for tunneling across a protein-protein interface. |
==About this Structure== | ==About this Structure== | ||
| - | 1I55 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thunnus_thynnus Thunnus thynnus] with HEM and ZNH as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1I55 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thunnus_thynnus Thunnus thynnus] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=ZNH:'>ZNH</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I55 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thunnus thynnus]] | [[Category: Thunnus thynnus]] | ||
| - | [[Category: Crane, B | + | [[Category: Crane, B R.]] |
| - | [[Category: Gray, H | + | [[Category: Gray, H B.]] |
| - | [[Category: Tezcan, F | + | [[Category: Tezcan, F A.]] |
| - | [[Category: Winkler, J | + | [[Category: Winkler, J R.]] |
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: ZNH]] | [[Category: ZNH]] | ||
| Line 23: | Line 23: | ||
[[Category: zinc-porphyrin]] | [[Category: zinc-porphyrin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:08:05 2008'' |
Revision as of 11:08, 21 February 2008
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CYTOCHROME C (TUNA) WITH 2ZN:1FE MIXED-METAL PORPHYRINS
Overview
The current understanding of electron tunneling through proteins has come from work on systems where donors and acceptors are held at fixed distances and orientations. The factors that control electron flow between proteins are less well understood, owing to uncertainties in the relative orientations and structures of the reactants during the very short time that tunneling occurs. As we report here, the way around such structural ambiguity is to examine oxidation-reduction reactions in protein crystals. Accordingly, we have measured and analyzed the kinetics of electron transfer between native and Zn-substituted tuna cytochrome c (cyt c) molecules in crystals of known structure. Electron transfer rates [(320 s(-1) for *Zn-cyt c --> Fe(III)-cyt c; 2000 s(-1) for Fe(II)-cyt c --> Zn-cyt c(+))] over a Zn-Fe distance of 24.1 A closely match those for intraprotein electron tunneling over similar donor-acceptor separations. Our results indicate that van der Waals interactions and water-mediated hydrogen bonds are effective coupling elements for tunneling across a protein-protein interface.
About this Structure
1I55 is a Single protein structure of sequence from Thunnus thynnus with and as ligands. Full crystallographic information is available from OCA.
Reference
Electron tunneling in protein crystals., Tezcan FA, Crane BR, Winkler JR, Gray HB, Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):5002-6. Epub 2001 Apr 10. PMID:11296248
Page seeded by OCA on Thu Feb 21 13:08:05 2008
