2akj
From Proteopedia
(New page: 200px<br /><applet load="2akj" size="450" color="white" frame="true" align="right" spinBox="true" caption="2akj, resolution 2.80Å" /> '''Structure of spinach...) |
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| - | [[Image:2akj.gif|left|200px]]<br /><applet load="2akj" size=" | + | [[Image:2akj.gif|left|200px]]<br /><applet load="2akj" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2akj, resolution 2.80Å" /> | caption="2akj, resolution 2.80Å" /> | ||
'''Structure of spinach nitrite reductase'''<br /> | '''Structure of spinach nitrite reductase'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of nitrite reductase, a key enzyme in the process of | + | The structure of nitrite reductase, a key enzyme in the process of nitrogen assimilation, has been determined using X-ray diffraction to a resolution limit of 2.8 A. The protein has a globular fold consisting of 3 alpha/beta domains with the siroheme-iron sulfur cofactor at the interface of the three domains. The Fe(4)S(4) cluster is coordinated by cysteines 441, 447, 482, and 486. The siroheme is located at a distance of 4.2 A from the cluster, and the central iron atom is coordinated to Cys 486. The siroheme is surrounded by several ionizable amino acid residues that facilitate the binding and subsequent reduction of nitrite. A model for the ferredoxin:nitrite reductase complex is proposed in which the binding of ferredoxin to a positively charged region of nitrite reductase results in elimination of exposure of the cofactors to the solvent. The structure of nitrite reductase shows a broad similarity to the hemoprotein subunit of sulfite reductase but has many significant differences in the backbone positions that could reflect sequence differences or could arise from alterations of the sulfite reductase structure that arise from the isolation of this subunit from the native complex. The implications of the nitrite reductase structure for understanding multi-electron processes are discussed in terms of differences in the protein environments of the cofactors. |
==About this Structure== | ==About this Structure== | ||
| - | 2AKJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Spinacia_oleracea Spinacia oleracea] with SF4 and SRM as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ferredoxin--nitrite_reductase Ferredoxin--nitrite reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.7.1 1.7.7.1] Full crystallographic information is available from [http:// | + | 2AKJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Spinacia_oleracea Spinacia oleracea] with <scene name='pdbligand=SF4:'>SF4</scene> and <scene name='pdbligand=SRM:'>SRM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ferredoxin--nitrite_reductase Ferredoxin--nitrite reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.7.1 1.7.7.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AKJ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Spinacia oleracea]] | [[Category: Spinacia oleracea]] | ||
| - | [[Category: Allen, J | + | [[Category: Allen, J P.]] |
[[Category: Hirasawa, M.]] | [[Category: Hirasawa, M.]] | ||
| - | [[Category: Kim, S | + | [[Category: Kim, S K.]] |
| - | [[Category: Knaff, D | + | [[Category: Knaff, D B.]] |
[[Category: Swamy, U.]] | [[Category: Swamy, U.]] | ||
| - | [[Category: Tripathy, J | + | [[Category: Tripathy, J N.]] |
[[Category: Wang, M.]] | [[Category: Wang, M.]] | ||
[[Category: SF4]] | [[Category: SF4]] | ||
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[[Category: x-ray crystallography; heme; electron transport]] | [[Category: x-ray crystallography; heme; electron transport]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:28:23 2008'' |
Revision as of 14:28, 21 February 2008
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Structure of spinach nitrite reductase
Overview
The structure of nitrite reductase, a key enzyme in the process of nitrogen assimilation, has been determined using X-ray diffraction to a resolution limit of 2.8 A. The protein has a globular fold consisting of 3 alpha/beta domains with the siroheme-iron sulfur cofactor at the interface of the three domains. The Fe(4)S(4) cluster is coordinated by cysteines 441, 447, 482, and 486. The siroheme is located at a distance of 4.2 A from the cluster, and the central iron atom is coordinated to Cys 486. The siroheme is surrounded by several ionizable amino acid residues that facilitate the binding and subsequent reduction of nitrite. A model for the ferredoxin:nitrite reductase complex is proposed in which the binding of ferredoxin to a positively charged region of nitrite reductase results in elimination of exposure of the cofactors to the solvent. The structure of nitrite reductase shows a broad similarity to the hemoprotein subunit of sulfite reductase but has many significant differences in the backbone positions that could reflect sequence differences or could arise from alterations of the sulfite reductase structure that arise from the isolation of this subunit from the native complex. The implications of the nitrite reductase structure for understanding multi-electron processes are discussed in terms of differences in the protein environments of the cofactors.
About this Structure
2AKJ is a Single protein structure of sequence from Spinacia oleracea with and as ligands. Active as Ferredoxin--nitrite reductase, with EC number 1.7.7.1 Full crystallographic information is available from OCA.
Reference
Structure of spinach nitrite reductase: implications for multi-electron reactions by the iron-sulfur:siroheme cofactor., Swamy U, Wang M, Tripathy JN, Kim SK, Hirasawa M, Knaff DB, Allen JP, Biochemistry. 2005 Dec 13;44(49):16054-63. PMID:16331965
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