1fp4
From Proteopedia
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| - | [[Image:1fp4.jpg|left|200px]] | + | [[Image:1fp4.jpg|left|200px]] |
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| - | '''CRYSTAL STRUCTURE OF THE ALPHA-H195Q MUTANT OF NITROGENASE''' | + | {{Structure |
| + | |PDB= 1fp4 |SIZE=350|CAPTION= <scene name='initialview01'>1fp4</scene>, resolution 2.5Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=HCA:3-HYDROXY-3-CARBOXY-ADIPIC+ACID'>HCA</scene>, <scene name='pdbligand=CFM:FE-MO-S+CLUSTER'>CFM</scene> and <scene name='pdbligand=CLP:FE-S CLUSTER'>CLP</scene> | ||
| + | |ACTIVITY= [http://en.wikipedia.org/wiki/Nitrogenase Nitrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.18.6.1 1.18.6.1] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''CRYSTAL STRUCTURE OF THE ALPHA-H195Q MUTANT OF NITROGENASE''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1FP4 is a [ | + | 1FP4 is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FP4 OCA]. |
==Reference== | ==Reference== | ||
| - | Mechanistic features and structure of the nitrogenase alpha-Gln195 MoFe protein., Sorlie M, Christiansen J, Lemon BJ, Peters JW, Dean DR, Hales BJ, Biochemistry. 2001 Feb 13;40(6):1540-9. PMID:[http:// | + | Mechanistic features and structure of the nitrogenase alpha-Gln195 MoFe protein., Sorlie M, Christiansen J, Lemon BJ, Peters JW, Dean DR, Hales BJ, Biochemistry. 2001 Feb 13;40(6):1540-9. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11327812 11327812] |
[[Category: Azotobacter vinelandii]] | [[Category: Azotobacter vinelandii]] | ||
[[Category: Nitrogenase]] | [[Category: Nitrogenase]] | ||
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[[Category: iron-sulfur-molybdenum protein]] | [[Category: iron-sulfur-molybdenum protein]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:12:07 2008'' |
Revision as of 09:12, 20 March 2008
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| , resolution 2.5Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , and | ||||||
| Activity: | Nitrogenase, with EC number 1.18.6.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF THE ALPHA-H195Q MUTANT OF NITROGENASE
Overview
EPR signals observed under CO and C(2)H(2) during nitrogenase turnover were investigated for the alpha-Gln(195) MoFe protein, an altered form for which the alpha-His(195) residue has been substituted by glutamine. Under CO, samples show S = 1/2 hi- and lo-CO EPR signals identical to those recognized for the wild-type protein, whereas the S = 3/2 signals generated under high CO/high flux conditions differ. Previous work has revealed that the EPR spectrum generated under C(2)H(2) exhibits a signal (S(EPR1)) originating from the FeMo-cofactor having two or more bound C(2)H(2) adducts and a second signal (S(EPR2)) arising from a radical species [Sorlie, M., Christiansen, J., Dean, D. R., and Hales, B. J. (1999) J. Am. Chem. Soc. 121, 9457-9458]. Pressure-dependent studies show that the intensity of these signals has a sigmoidal dependency at low pressures and maximized at 0.1 atm C(2)H(2) with a subsequent decrease in steady-state intensity at higher pressures. Analogous signals are not recognized for the wild-type MoFe protein. Analysis of the principal g-factors of S(EPR2) suggests that it either represents an unusual metal cluster or is a carboxylate centered radical possibly originating from homocitrate. Both S(EPR1) and S(EPR2) exhibit similar relaxation properties that are atypical for S = 1/2 signals originating from Fe-S clusters or radicals and indicate a coupled relaxation pathway. The alpha-Gln(195) MoFe protein also exhibits these signals when incubated under turnover conditions in the presence of C(2)H(4). Under these conditions, additional inflections in the g 4-6 region assigned to ground-state transitions of an S = 3/2 spin system are also recognized and assigned to turnover states of the MoFe protein without C(2)H(4) bound. The structure of alpha-Gln(195) was crystallographically determined and found to be virtually identical to that of the wild-type MoFe protein except for replacement of an NuH-S hydrogen bond interaction between FeMo-cofactor and the imidazole side chain of alpha-His(195) by an analogous interaction involving Gln.
About this Structure
1FP4 is a Protein complex structure of sequences from Azotobacter vinelandii. Full crystallographic information is available from OCA.
Reference
Mechanistic features and structure of the nitrogenase alpha-Gln195 MoFe protein., Sorlie M, Christiansen J, Lemon BJ, Peters JW, Dean DR, Hales BJ, Biochemistry. 2001 Feb 13;40(6):1540-9. PMID:11327812
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