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1siw
From Proteopedia
(New page: 200px<br /><applet load="1siw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1siw, resolution 2.20Å" /> '''Crystal structure of...) |
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| - | [[Image:1siw.gif|left|200px]]<br /><applet load="1siw" size=" | + | [[Image:1siw.gif|left|200px]]<br /><applet load="1siw" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1siw, resolution 2.20Å" /> | caption="1siw, resolution 2.20Å" /> | ||
'''Crystal structure of the apomolybdo-NarGHI'''<br /> | '''Crystal structure of the apomolybdo-NarGHI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We have used EPR spectroscopy, redox potentiometry, and protein | + | We have used EPR spectroscopy, redox potentiometry, and protein crystallography to characterize the [4Fe-4S] cluster (FS0) of the Escherichia coli nitrate reductase A (NarGHI) catalytic subunit (NarG). FS0 is clearly visible in the crystal structure of NarGHI [Bertero, M. G., et al. (2003) Nat. Struct. Biol. 10, 681-687] but has novel coordination comprising one His residue and three Cys residues. At low temperatures (<15 K), reduced NarGHI exhibits a previously unobserved EPR signal comprising peaks at g = 5.023 and g = 5.556. We have assigned these features to a [4Fe-4S](+) cluster with an S = (3)/(2) ground state, with the g = 5.023 and g = 5.556 peaks corresponding to subpopulations exhibiting DeltaS = (1)/(2) and DeltaS = (3)/(2) transitions, respectively. Both peaks exhibit midpoint potentials of approximately -55 mV at pH 8.0 and are eliminated in the EPR spectrum of apomolybdo-NarGHI. The structure of apomolybdo-NarGHI reveals that FS0 is still present but that there is significant conformational disorder in a segment of residues that includes one of the Cys ligands. On the basis of these observations, we have assigned the high-spin EPR features of reduced NarGHI to FS0. |
==About this Structure== | ==About this Structure== | ||
| - | 1SIW is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with GDP, HEM, SF4, F3S and 3PH as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Nitrate_reductase Nitrate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.99.4 1.7.99.4] Full crystallographic information is available from [http:// | + | 1SIW is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=GDP:'>GDP</scene>, <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=SF4:'>SF4</scene>, <scene name='pdbligand=F3S:'>F3S</scene> and <scene name='pdbligand=3PH:'>3PH</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Nitrate_reductase Nitrate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.99.4 1.7.99.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SIW OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Nitrate reductase]] | [[Category: Nitrate reductase]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Bertero, M | + | [[Category: Bertero, M G.]] |
[[Category: Blasco, F.]] | [[Category: Blasco, F.]] | ||
[[Category: Cammack, R.]] | [[Category: Cammack, R.]] | ||
[[Category: Palak, M.]] | [[Category: Palak, M.]] | ||
| - | [[Category: Rothery, R | + | [[Category: Rothery, R A.]] |
| - | [[Category: Strynadka, N | + | [[Category: Strynadka, N C.]] |
| - | [[Category: Weiner, J | + | [[Category: Weiner, J H.]] |
[[Category: 3PH]] | [[Category: 3PH]] | ||
[[Category: F3S]] | [[Category: F3S]] | ||
| Line 28: | Line 28: | ||
[[Category: apomolybdo-narghi; electron-transfer; membrane protein]] | [[Category: apomolybdo-narghi; electron-transfer; membrane protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:01:55 2008'' |
Revision as of 13:02, 21 February 2008
|
Crystal structure of the apomolybdo-NarGHI
Overview
We have used EPR spectroscopy, redox potentiometry, and protein crystallography to characterize the [4Fe-4S] cluster (FS0) of the Escherichia coli nitrate reductase A (NarGHI) catalytic subunit (NarG). FS0 is clearly visible in the crystal structure of NarGHI [Bertero, M. G., et al. (2003) Nat. Struct. Biol. 10, 681-687] but has novel coordination comprising one His residue and three Cys residues. At low temperatures (<15 K), reduced NarGHI exhibits a previously unobserved EPR signal comprising peaks at g = 5.023 and g = 5.556. We have assigned these features to a [4Fe-4S](+) cluster with an S = (3)/(2) ground state, with the g = 5.023 and g = 5.556 peaks corresponding to subpopulations exhibiting DeltaS = (1)/(2) and DeltaS = (3)/(2) transitions, respectively. Both peaks exhibit midpoint potentials of approximately -55 mV at pH 8.0 and are eliminated in the EPR spectrum of apomolybdo-NarGHI. The structure of apomolybdo-NarGHI reveals that FS0 is still present but that there is significant conformational disorder in a segment of residues that includes one of the Cys ligands. On the basis of these observations, we have assigned the high-spin EPR features of reduced NarGHI to FS0.
About this Structure
1SIW is a Protein complex structure of sequences from Escherichia coli with , , , and as ligands. Active as Nitrate reductase, with EC number 1.7.99.4 Full crystallographic information is available from OCA.
Reference
The catalytic subunit of Escherichia coli nitrate reductase A contains a novel [4Fe-4S] cluster with a high-spin ground state., Rothery RA, Bertero MG, Cammack R, Palak M, Blasco F, Strynadka NC, Weiner JH, Biochemistry. 2004 May 11;43(18):5324-33. PMID:15122898
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