1lkp
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1lkp.gif|left|200px]] | [[Image:1lkp.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1lkp", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1lkp| PDB=1lkp | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''Crystal structure of Desulfovibrio vulgaris rubrerythrin all-iron(II) form, azide adduct''' | '''Crystal structure of Desulfovibrio vulgaris rubrerythrin all-iron(II) form, azide adduct''' | ||
| Line 30: | Line 27: | ||
[[Category: Rose, J.]] | [[Category: Rose, J.]] | ||
[[Category: Wang, B C.]] | [[Category: Wang, B C.]] | ||
| - | [[Category: | + | [[Category: Azide adduct]] |
| - | [[Category: | + | [[Category: Diiron]] |
| - | [[Category: | + | [[Category: Four-helix bundle]] |
| - | [[Category: | + | [[Category: Reduced form]] |
| - | [[Category: | + | [[Category: Rubredoxin-like]] |
| - | [[Category: | + | [[Category: Rubrerythrin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 00:00:52 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 21:00, 2 May 2008
Crystal structure of Desulfovibrio vulgaris rubrerythrin all-iron(II) form, azide adduct
Overview
Rubrerythrin (Rbr) is a 44-kDa homodimeric protein, found in many air-sensitive bacteria and archaea, which contains a unique combination of a rubredoxin-like [Fe(SCys)(4)] site and a non-sulfur, oxo/dicarboxylato-bridged diiron site. The diiron site structure resembles those found in O2-activating diiron enzymes. However, Rbr instead appears to function as a hydrogen peroxide reductase (peroxidase). The diferrous site in all-ferrous Rbr (Rbr(red)) shows a much greater reactivity with H2O2 than does the diferric site in all-ferric Rbr (Rbr(ox)), but only the latter structure has been reported. Here we report the X-ray crystal structures of the recombinant Rbr(red) from the sulfate reducing bacterium, Desulfovibrio vulgaris, as well as its azide adduct (Rbr(red)N3). We have also redetermined the structure of Rbr(ox) to a higher resolution than previously reported. The structural differences between Rbr(ox) and Rbr(red) are localized entirely at the diiron site. The most striking structural change upon reduction of the diferric to the diferrous site of Rbr is a 1.8-A movement of one iron away from a unique glutamate carboxylate ligand and toward a trans-disposed histidine side chain, which replaces the glutamate as a ligand. This movement increases the inter-iron distance from 3.3 to 4 A. Rbr(red)N(3) shows this same iron movement and His-->Glu ligand replacement relative to Rbr(ox), and, in addition, an azide coordinated to the diiron site in a cis mu-1,3 fashion, replacing two solvent ligands in Rbr(red). Relative to those in O2-activating enzymes, the bridging carboxylate ligation of the Rbr diiron site is less flexible upon diferric/diferrous interconversion. The diferrous site is also much more rigid, symmetrical, and solvent-exposed than those in O2-activating enzymes. On the basis of these unique structural features, a mechanism is proposed for facile reduction of hydrogen peroxide by Rbr involving a cis mu-eta(2) H2O2 diferrous intermediate.
About this Structure
1LKP is a Single protein structure of sequence from Desulfovibrio vulgaris. Full crystallographic information is available from OCA.
Reference
X-ray crystal structures of reduced rubrerythrin and its azide adduct: a structure-based mechanism for a non-heme diiron peroxidase., Jin S, Kurtz DM Jr, Liu ZJ, Rose J, Wang BC, J Am Chem Soc. 2002 Aug 21;124(33):9845-55. PMID:12175244 Page seeded by OCA on Sat May 3 00:00:52 2008
