1ycf
From Proteopedia
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Oxidized (di-ferric) FprA from Moorella thermoacetica
Overview
Several members of a widespread class of bacterial and archaeal, metalloflavoproteins, called FprA, likely function as scavenging nitric, oxide reductases (S-NORs). However, the only published X-ray crystal, structure of an FprA is for a protein characterized as a, rubredoxin:dioxygen oxidoreductase (ROO) from Desulfovibrio gigas., Therefore, the crystal structure of Moorella thermoacetica FprA, which has, been established to function as an S-NOR, was solved in three different, states: as isolated, reduced, and reduced, NO-reacted. As is the case for, D. gigas ROO, the M. thermoacetica FprA contains a solvent-bridged, non-heme, non-sulfur diiron site with five-coordinate iron centers bridged, by an aspartate, and terminal glutamate, aspartate, and histidine ligands., However, the M. thermoacetica FprA diiron site showed four His ligands, two to each iron, in all three states, whereas the D. gigas ROO diiron, site was reported to contain only three His ligands, even though the, fourth His residue is conserved. The Fe1-Fe2 distance within the diiron, site of M. thermoacetica FprA remained at 3.2-3.4 A with little or no, movement of the protein ligands in the three different states and with, conservation of the two proximal open coordination sites. Molecular, modeling indicated that each open coordination site can accommodate an, end-on NO. This relatively rigid and symmetrical diiron site structure is, consistent with formation of a diferrous dinitrosyl as the committed, catalytic intermediate leading to formation of N(2)O. These results, provide new insight into the structural features that fine-tune biological, non-heme diiron sites for dioxygen activation vs nitric oxide reduction.
About this Structure
1YCF is a Single protein structure of sequence from Moorella thermoacetica with ZN, FEO, OXY and FMN as ligands. Full crystallographic information is available from OCA.
Reference
X-ray crystal structures of Moorella thermoacetica FprA. Novel diiron site structure and mechanistic insights into a scavenging nitric oxide reductase., Silaghi-Dumitrescu R, Kurtz DM Jr, Ljungdahl LG, Lanzilotta WN, Biochemistry. 2005 May 3;44(17):6492-501. PMID:15850383
Page seeded by OCA on Wed Nov 21 06:40:51 2007
