We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Characterization and Crystallization of an IscU-type Scaffold Protein with Bound [2Fe–2S] Cluster from the Hyperthermophile, Aquifex aeolicus.
- Authors
Shimomura, Yoshimitsu; Kamikubo, Hironari; Nishi, Yoshinori; Masako, Takuya; Kataoka, Mikio; Kobayashi, Yuji; Fukuyama, Keiichi; Takahashi, Yasuhiro
- Abstract
IscU plays a key role during iron–sulphur (Fe–S) cluster biosynthesis as a scaffold for the assembly of a nascent, highly labile Fe–S cluster. Here we report the characterization of an IscU-type protein (Aa IscU) from the hyperthermophilic bacterium Aquifex aeolicus. Unlike other known homologues of IscU, expression of Aa IscU in Escherichia coli has yielded an Fe–S cluster-containing holo-protein. Biochemical and spectroscopic studies of the wild-type Aa IscU and its Asp38-to-Ala substituted (D38A) variant molecule indicate that the holo-protein forms a trimer containing substoichiometric [2Fe–2S] cluster with its stability substantially increased by a D38A substitution. The [2Fe–2S] cluster was oxygen-labile and upon loss of the cluster, the resultant apo-form dissociated into a smaller species, a mixture of monomer and dimer with the dimer form predominating. Reddish-brown crystals of holo-Aa IscU-D38A were obtained under anaerobic conditions, that gave diffractions beyond 2.0 Å resolution with synchrotron radiation. The crystal belongs to the space group P21212 with unit-cell parameters a = 72.6, b = 122.3, c = 62.4 Å, where the asymmetric unit contains three molecules of Aa IscU. Successful crystallization of holo-Aa IscU-D38A strongly suggests that the trimer association carrying substoichiometric [2Fe–2S] cluster represents a conformationally stable oligomeric state.
- Subjects
CRYSTALLIZATION; PROTEINS; ESCHERICHIA coli; ENTEROBACTERIACEAE; BIOCHEMICAL templates
- Publication
Journal of Biochemistry, 2007, Vol 142, Issue 5, p577
- ISSN
0021-924X
- Publication type
Article
- DOI
10.1093/jb/mvm163