4dhv

From Proteopedia

Crystal structure of the Pyrococcus furiosus ferredoxin D14C variant containing the heterometallic [AgFe3S4] cluster

Structural highlights

4dhv is a 2 chain structure with sequence from Pyrococcus furiosus DSM 3638. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.95Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

FER_PYRFU Ferredoxins are iron-sulfur proteins that transfer electrons in a wide variety of metabolic reactions.

Publication Abstract from PubMed

Heterometallic [AgFe(3)S(4)] iron-sulfur clusters assembled in wild-type Pyrococcus furiosus ferredoxin and two variants, D14C and D14H, are characterized. The crystal structure of the [AgFe(3)S(4)] D14C variant shows that the silver(I) ion is indeed part of the cluster and is coordinated to the thiolate group of residue 14. Cyclic voltammetry shows one redox pair with a reduction potential of +220 mV versus the standard hydrogen electrode which is assigned to the [AgFe(3)S(4)](2+/+) couple. The oxidized form of the [AgFe(3)S(4)] D14C variant is stable in the presence of dioxygen, whereas the oxidized forms of the [AgFe(3)S(4)] wild type and D14H variants convert to the [Fe(3)S(4)] ferredoxin form. The monovalent d (10) silver(I) ion stabilizes the [Fe(3)S(4)](+/0) cluster fragment, as opposed to divalent d (10) metal ions, resulting in more than 0.4 V difference in reduction potentials between the silver(I) and, e.g., zinc(II) heterometallic [MFe(3)S(4)] ferredoxins. The trend in reduction potentials for the variants containing the [AgFe(3)S(4)] cluster is wild type </= D14C < D14H and shows the same trend as reported for the variants containing the [Fe(3)S(4)] cluster, but is different from the D14C < D14H < wild type trend reported for the [Fe(4)S(4)] ferredoxin. The similarity in the reduction potential trend for the variants containing the heterometallic [AgFe(3)S(4)] cluster and the [Fe(3)S(4)] cluster can be rationalized in terms of the electrostatic influence of the residue 14 side chains, rather than the dissociation constant of this residue, as is the case for [Fe(4)S(4)] ferredoxins. The trends in reduction potentials are in line with there being no electronic coupling between the silver(I) ion and the Fe(3)S(4) fragment.

Heterometallic [AgFe(3)S (4)] ferredoxin variants: synthesis, characterization, and the first crystal structure of an engineered heterometallic iron-sulfur protein.,Martic M, Jakab-Simon IN, Haahr LT, Hagen WR, Christensen HE J Biol Inorg Chem. 2013 Feb;18(2):261-76. doi: 10.1007/s00775-012-0971-3. Epub, 2013 Jan 8. PMID:23296387^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Martic M, Jakab-Simon IN, Haahr LT, Hagen WR, Christensen HE. Heterometallic [AgFe(3)S (4)] ferredoxin variants: synthesis, characterization, and the first crystal structure of an engineered heterometallic iron-sulfur protein. J Biol Inorg Chem. 2013 Feb;18(2):261-76. doi: 10.1007/s00775-012-0971-3. Epub, 2013 Jan 8. PMID:23296387 doi:10.1007/s00775-012-0971-3