1s30
From Proteopedia
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X-ray crystal structure of Desulfovibrio vulgaris Rubrerythrin with displacement of iron by zinc at the diiron Site
Overview
X-ray crystal structures of recombinant Desulfovibrio (D.) vulgaris, rubrerythrin (Rbr) have shown a diiron site, whereas the crystal structure, of Rbr "as-isolated" from D. vulgaris was reported to contain a mixed, Zn,Fe binuclear site. To investigate the possibility that zinc had, displaced iron during isolation or crystallization of the "as-isolated" D., vulgaris Rbr, the X-ray crystal structure of recombinant D. vulgaris, all-iron Rbr that had been incubated with excess zinc sulfate prior to, crystallization, yielding a protein labeled Zn,FeRbr, was solved. Analysis, of the anomalous scattering data obtained at two different wavelengths, showed that zinc had displaced a significant proportion of iron from both, iron centers of the diiron site, and that no iron had been displaced from, the [Fe(SCys)(4)] site. UV-visible absorption spectra of the redissolved, Zn,FeRbr crystals showed 30-40% retention of oxo-bridged diferric sites, and the redissolved crystals had 37% of the peroxidase specific activity, of the starting all-iron Rbr, which, together with the crystallographic, results, indicate a predominant mixture of Fe1,Fe2 and Zn1,Zn2 sites. The, structure of the Zn(Fe)1,Fe(Zn)2 binuclear site in the Zn,FeRbr crystals, was very similar to that of the Zn,Fe binuclear site reported for the, "as-isolated" D. vulgaris Rbr, including tetrahedral four-coordination at, the Zn(Fe)1 site. The diiron sites in the recombinant Zn,FeRbr crystals, were likely at least partially reduced during synchrotron irradiation. Our, results suggest that the mixed-metal binuclear site reported for the, "as-isolated" D. vulgaris Rbr could be due to displacement of iron from a, native diiron site by adventitious zinc during isolation and/or, crystallization, and that reduced diiron and dizinc sites can adopt very, similar structures in Rbr.
About this Structure
1S30 is a Single protein structure of sequence from Desulfovibrio vulgaris with FE and ZN as ligands. Full crystallographic information is available from OCA.
Reference
Displacement of iron by zinc at the diiron site of Desulfovibrio vulgaris rubrerythrin: X-ray crystal structure and anomalous scattering analysis., Jin S, Kurtz DM Jr, Liu ZJ, Rose J, Wang BC, J Inorg Biochem. 2004 May;98(5):786-96. PMID:15134924
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