1ddi: Difference between revisions
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[[Image:1ddi.gif|left|200px]] | [[Image:1ddi.gif|left|200px]] | ||
'''CRYSTAL STRUCTURE OF SIR-FP60''' | {{Structure | ||
|PDB= 1ddi |SIZE=350|CAPTION= <scene name='initialview01'>1ddi</scene>, resolution 2.51Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene> and <scene name='pdbligand=NAP:NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE'>NAP</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Sulfite_reductase_(NADPH) Sulfite reductase (NADPH)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.8.1.2 1.8.1.2] | |||
|GENE= | |||
}} | |||
'''CRYSTAL STRUCTURE OF SIR-FP60''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1DDI is a [ | 1DDI is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DDI OCA]. | ||
==Reference== | ==Reference== | ||
Four crystal structures of the 60 kDa flavoprotein monomer of the sulfite reductase indicate a disordered flavodoxin-like module., Gruez A, Pignol D, Zeghouf M, Coves J, Fontecave M, Ferrer JL, Fontecilla-Camps JC, J Mol Biol. 2000 May 26;299(1):199-212. PMID:[http:// | Four crystal structures of the 60 kDa flavoprotein monomer of the sulfite reductase indicate a disordered flavodoxin-like module., Gruez A, Pignol D, Zeghouf M, Coves J, Fontecave M, Ferrer JL, Fontecilla-Camps JC, J Mol Biol. 2000 May 26;299(1):199-212. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10860732 10860732] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: modular protein]] | [[Category: modular 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 10:36:45 2008'' | ||
Revision as of 08:36, 20 March 2008
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| 1ddi, resolution 2.51Å | |||||||||||||
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| Ligands: | FAD and NAP | ||||||||||||
| Activity: | Sulfite reductase (NADPH), with EC number 1.8.1.2 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
CRYSTAL STRUCTURE OF SIR-FP60
Overview
Escherichia coli NADPH-sulfite reductase (SiR) is a 780 kDa multimeric hemoflavoprotein composed of eight alpha-subunits (SiR-FP) and four beta-subunits (SiR-HP) that catalyses the six electron reduction of sulfite to sulfide. Each beta-subunit contains a Fe4S4 cluster and a siroheme, and each alpha-subunit binds one FAD and one FMN as prosthetic groups. The FAD gets electrons from NADPH, and the FMN transfers the electrons to the metal centers of the beta-subunit for sulfite reduction. We report here the 1.94 A X-ray structure of SiR-FP60, a recombinant monomeric fragment of SiR-FP that binds both FAD and FMN and retains the catalytic properties of the native protein. The structure can be divided into three domains. The carboxy-terminal part of the enzyme is composed of an antiparallel beta-barrel which binds the FAD, and a variant of the classical pyridine dinucleotide binding fold which binds NADPH. These two domains form the canonic FNR-like module, typical of the ferredoxin NADP+ reductase family. By analogy with the structure of the cytochrome P450 reductase, the third domain, composed of seven alpha-helices, is supposed to connect the FNR-like module to the N-terminal flavodoxine-like module. In four different crystal forms, the FMN-binding module is absent from electron density maps, although mass spectroscopy, amino acid sequencing and activity experiments carried out on dissolved crystals indicate that a functional module is present in the protein. Our results clearly indicate that the interaction between the FNR-like and the FMN-like modules displays lower affinity than in the case of cytochrome P450 reductase. The flexibility of the FMN-binding domain may be related, as observed in the case of cytochrome bc1, to a domain reorganisation in the course of electron transfer. Thus, a movement of the FMN-binding domain relative to the rest of the enzyme may be a requirement for its optimal positioning relative to both the FNR-like module and the beta-subunit.
About this Structure
1DDI is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Four crystal structures of the 60 kDa flavoprotein monomer of the sulfite reductase indicate a disordered flavodoxin-like module., Gruez A, Pignol D, Zeghouf M, Coves J, Fontecave M, Ferrer JL, Fontecilla-Camps JC, J Mol Biol. 2000 May 26;299(1):199-212. PMID:10860732
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