TY - JOUR
T1 - The 'prismane' protein resolved: X-ray structure at 1.7 Å and multiple spectroscopy of two novel 4Fe clusters
AU - Arendsen, Alexander F.
AU - Hadden, Jonathan
AU - Card, Graeme
AU - McAlpine, Alan S.
AU - Bailey, Susan
AU - Zaitsev, Vjacheslav
AU - Duke, Elizabeth H.M.
AU - Lindley, Peter F.
AU - Kröckel, Monika
AU - Trautwein, Alfred X.
AU - Feiters, Martinus C.
AU - Charnock, John M.
AU - Garner, C. David
AU - Marritt, Sophie J.
AU - Thomson, Andrew J.
AU - Kooter, Ingeborg M.
AU - Johnson, Michael K.
AU - Van Den Berg, Willy A.M.
AU - Van Dongen, Walter M.A.M.
AU - Hagen, Wilfred R.
PY - 1998/2/1
Y1 - 1998/2/1
N2 - The three-dimensional structure of the native 'putative prismane' protein from Desulfovibrio vulgaris (Hildenborough) has been solved by X-ray crystallography to a resolution of 1.72 Å. The molecule does not contain a [6Fe-6S] prismane cluster, but rather two 4Fe clusters some 12 Å apart and situated close to the interfaces formed by the three domains of the protein. Cluster 1 is a conventional [4Fe-4S] cubane bound, however, near the N- terminus by an unusual, sequential arrangement of four cysteine residues (Cys 3, 6, 15, 21). Cluster 2 is a novel 4Fe structure with two μ2-sulfido bridges, two μ2-oxo bridges, and a partially occupied, unidentified μ2 bridge X. The protein ligands of cluster 2 are widely scattered through the second half of the sequence and include three cysteine residues (Cys 312, 434, 459), one persulfido-cysteine (Cys 406), two glutamates (Glu 268, 494), and one histidine (His 244). With this unusual mixture of bridging and external type of ligands, cluster 2 is named the 'hybrid' cluster, and its asymmetric, open structure suggests that it could be the site of a catalytic activity. X-ray absorption spectroscopy at the Fe K-edge is readily interpretable in terms of the crystallographic model when allowance is made for volume contraction at 10K; no Fe··Fe distances beyond 3.1 Å could be identified. EPR, Mossbauer and MCD spectroscopy have been used to define the oxidation states and the magnetism of the clusters in relation to the crystallographic structure. Reduced cluster 1 is a [4Fe-4S]1+ cubane with S = 3/2; it is the first biological example of a 'spin-admixed' iron-sulfur cluster. The hybrid cluster 2 has four oxidation states from (formally) all Fe(III) to three Fe(II) plus one Fe(III). The four iron ions are exchange coupled resulting in the system spins S = 0, 9/2, 0 (and 4), 1/2, respectively for the four redox states. Resonance Raman spectroscopy suggests that the bridging ligand X which could not be identified unambiguously in the crystal structure is a solvent-exchangeable oxygen.
AB - The three-dimensional structure of the native 'putative prismane' protein from Desulfovibrio vulgaris (Hildenborough) has been solved by X-ray crystallography to a resolution of 1.72 Å. The molecule does not contain a [6Fe-6S] prismane cluster, but rather two 4Fe clusters some 12 Å apart and situated close to the interfaces formed by the three domains of the protein. Cluster 1 is a conventional [4Fe-4S] cubane bound, however, near the N- terminus by an unusual, sequential arrangement of four cysteine residues (Cys 3, 6, 15, 21). Cluster 2 is a novel 4Fe structure with two μ2-sulfido bridges, two μ2-oxo bridges, and a partially occupied, unidentified μ2 bridge X. The protein ligands of cluster 2 are widely scattered through the second half of the sequence and include three cysteine residues (Cys 312, 434, 459), one persulfido-cysteine (Cys 406), two glutamates (Glu 268, 494), and one histidine (His 244). With this unusual mixture of bridging and external type of ligands, cluster 2 is named the 'hybrid' cluster, and its asymmetric, open structure suggests that it could be the site of a catalytic activity. X-ray absorption spectroscopy at the Fe K-edge is readily interpretable in terms of the crystallographic model when allowance is made for volume contraction at 10K; no Fe··Fe distances beyond 3.1 Å could be identified. EPR, Mossbauer and MCD spectroscopy have been used to define the oxidation states and the magnetism of the clusters in relation to the crystallographic structure. Reduced cluster 1 is a [4Fe-4S]1+ cubane with S = 3/2; it is the first biological example of a 'spin-admixed' iron-sulfur cluster. The hybrid cluster 2 has four oxidation states from (formally) all Fe(III) to three Fe(II) plus one Fe(III). The four iron ions are exchange coupled resulting in the system spins S = 0, 9/2, 0 (and 4), 1/2, respectively for the four redox states. Resonance Raman spectroscopy suggests that the bridging ligand X which could not be identified unambiguously in the crystal structure is a solvent-exchangeable oxygen.
UR - http://www.scopus.com/inward/record.url?scp=12144286845&partnerID=8YFLogxK
U2 - 10.1007/s007750050210
DO - 10.1007/s007750050210
M3 - Journal articles
AN - SCOPUS:12144286845
SN - 0949-8257
VL - 3
SP - 81
EP - 95
JO - Journal of Biological Inorganic Chemistry
JF - Journal of Biological Inorganic Chemistry
IS - 1
ER -